Usefulness of Cdx2 in separating mucinous bronchioloalveolar adenocarcinoma of the lung from metastatic mucinous colorectal adenocarcinoma.

We studied the diagnostic value of Cdx2 to distinguish mucinous bronchioloalveolar carcinoma from mucinous colorectal adenocarcinoma metastatic to the lung. We retrieved 92 via the hospital computer system, including 30 mucinous bronchioloalveolar carcinomas, 32 nonmucinous bronchioloalveolar carcinomas, and 30 mucinous colorectal adenocarcinomas metastatic to the lung. All cases were confirmed by clinical history and surgical resection with occasional immunohistochemical studies. Cases were stained with antibodies against Cdx2, thyroid transcription factor-1 (TTF-1), cytokeratin (CK) 7, and CK20. Bronchioloalveolar carcinoma, mucinous type, showed positive staining for Cdx2, TTF-1, CK7, and CK20 in 0 (0%), 5 (17%), 30 (100%), and 18 (60%) of 30 cases, respectively; nonmucinous tumors were positive in 0 (0%), 30 (94%), 32 (100%), and 0 (0%) of 32 cases, respectively. For colorectal adenocarcinoma, the positive staining for Cdx-2, TTF-1, CK7, and CK20 was 29 (97%), 0 (0%), 7 (23%), and 29 (97%) of 30 cases, respectively. Our results demonstrated Cdx2 as a sensitive and specific marker for differentiating metastatic colorectal adenocarcinoma from mucinous bronchioloalveolar adenocarcinoma.

Related papers:

title: Surgical treatment of hepatic and pulmonary metastases from colon cancer.
abstract: Surgical resection of isolated hepatic or pulmonary metastases secondary to colorectal cancer has been shown to yield acceptable long-term survival. However, results are inconclusive for surgical resection of both hepatic and pulmonary metastases.



We reviewed the records of all patients who underwent surgical resection of both hepatic and pulmonary metastases from colorectal cancer between 1980 and 1998.



A total of 58 patients underwent resection of both hepatic and pulmonary metastases secondary to colorectal cancer. All patients had local control of their primary cancer before metastasectomy. There were no operative deaths. Morbidity occurred in 12% of patients. Follow-up was complete in all patients, with a median duration of 62 months (range, 6 to 201 months). The 5- and 10-year survivals were 30% and 16%, respectively. A premetastasectomy carcinoembryonic antigen level greater than 5 ng/mL increased the risk of early death (p = 0.029). Neither the number of pulmonary lesions nor the time interval between the primary surgery and the metastasectomy had a significant impact on survival (p = 0.67). At 5 years, 55% of patients were free of disease. Four patients had lymph node involvement at the time of pulmonary resection and all 4 patients died within 22 months of their pulmonary metastasectomy.



Resection of both hepatic and pulmonary metastases secondary to colorectal cancer in highly selected patients is safe and results in long-term survival. Thoracic lymph node involvement and elevated carcinoembryonic antigen levels before pulmonary metastasectomy are associated with reduced survival.

title: Utility of cytokeratin immunostaining in separating pulmonary adenocarcinomas from colonic adenocarcinomas.
abstract: Adenocarcinomas of uncertain origin are a frequent problem for surgical pathologists. To determine the utility of immunostaining for cytokeratin 7 and cytokeratin 20 in the separation of pulmonary adenocarcinomas from colonic adenocarcinomas, we studied routinely processed, formalin-fixed tissue from 151 of these tumors using commercially available monoclonal antibodies and an avidin-biotin immunohistochemical technique. Used alone, neither cytokeratin 7 immunostaining or cytokeratin 20 immunostaining reliably separated these tumors. However, the immunophenotype of cytokeratin 7 positive/cytokeratin 20 negative was seen in 86% of the pulmonary adenocarcinomas, and in 0% of the colonic adenocarcinomas. Conversely, the cytokeratin 7-negative/cytokeratin 20-positive immunophenotype was seen in 77% of the colonic carcinomas, and in 0% of the pulmonary tumors. In conclusion, cytokeratin 7/cytokeratin 20 immunostaining patterns may be helpful in separating pulmonary adenocarcinomas from colonic adenocarcinomas.

title: Cytokeratins 7 and 20 and carcinoembryonic antigen in ovarian and colonic carcinoma.
abstract: The histologic distinction between adenocarcinoma primary to the ovary and metastatic to the ovary can be difficult. In an effort to facilitate this distinction, we have evaluated the use of immunohistochemical techniques with antibodies to cytokeratins 7 and 20, along with antibodies to carcinoembryonic antigen. We studied 24 primary ovarian adenocarcinomas, 11 colonic adenocarcinomas metastatic to the ovary, and 10 primary adenocarcinomas of the colon. Four ovarian adenocarcinomas metastatic to the colon were also studied. All but one of the primary and metastatic colonic carcinomas were negative for cytokeratin 7, whereas all the primary and metastatic ovarian carcinomas were positive for cytokeratin 7. The tumors metastatic to the ovary were all positive for cytokeratin 20 and carcinoembryonic antigen. Among the primary ovarian carcinomas, none of six serous tumors, three of seven endometrioid tumors, and three of 11 mucinous tumors were positive for cytokeratin 20. Ten of the primary ovarian tumors were negative for carcinoembryonic antigen using both monoclonal and polyclonal antibodies. One of the ovarian tumors was negative for carcinoembryonic antigen with the monoclonal antibody but positive using the polyclonal antibody. Cytokeratin 7 is the most helpful marker in the distinction between primary ovarian carcinoma and colonic carcinoma metastatic to the ovary.

title: Use of thyroid transcription factor 1, PE‐10, and cytokeratins 7 and 20 in discriminating between primary lung carcinomas and metastatic lesions in fine‐needle aspiration biopsy specimens
abstract: The distinction of a primary lung carcinoma from a metastatic lesion is important, because the treatment and prognosis differ for patients with these malignancies. Such a distinction can be difficult because of overlapping cytologic features. It has been shown that antibodies to thyroid transcription factor 1 (TTF‐1) and PE‐10 are fairly specific markers for primary lung tumors in histologic specimens. TTF‐1 regulates the expression of surfactant protein production, and PE‐10 is a monoclonal antibody against components of human surfactant proteins. The combination of cytokeratin 7 (CK7) and cytokeratin 20 (CK20) immunoprofiling has been helpful in the identification of the primary site of origin of lung tumors.

title: Immunohistologic evaluation of metastatic carcinomas of unknown origin: an algorithmic approach.
abstract: Pathologists are now asked frequently to determine the primary site for metastatic carcinomas of unknown origin (MCUO), using adjunctive morphological techniques such as electron microscopy, immunohistology, and other modalities. The authors present an algorithmic immunohistochemical approach to this problem that is based on their experience with over 2,800 routinely-processed epithelial malignancies of various types. These have been studied with antibodies to keratins, vimentin, epithelial membrane antigen, MOC-31, tumor associated-glycoprotein-72 (recognized by monoclonal antibody B72.3), prostate-specific antigen, thyroglobulin, gross cystic disease fluid protein-15, carcinoembryonic antigen, CA-125, CA19-9, placental alkaline phosphatase, S100 protein, and estrogen receptor protein. The algorithm that is structured around these 14 analytes is based on the relative predictive value of each marker, which in turn, determines its place in the sequence of interpretation. The authors' experience with this approach shows 67% accuracy with regard to the ultimately determined site of origin for MCUO, a figure which is similar to that reported by other investigators.

title: Cytokeratin 7 Immunoreactivity in Rectal Adenocarcinomas
abstract: Colonic mucosa typically expresses cytokeratin (CK) 20 but not CK7. This CK20+/CK7− profile has been used to distinguish colonic adenocarcinoma from others arising in the lung, breast, or genitourinary tract. CK7 expression in colorectal adenocarcinoma has been reported to be rare, and when present, a metastatic origin needs to be excluded. However, we have observed a higher frequency of CK7 positivity in rectal adenocarcinomas. Paraffin sections of 42 rectal tumors (7 adenomas and 35 adenocarcinomas), 11 colonic adenocarcinomas proximal to the rectum, and 18 nonneoplastic rectoanal mucosa were randomly selected and immunostained for CK7 and CK20 with a standard avidin-biotin complex method. Immunoreactivity was recorded semiquantitatively. Cytoplasmic CK7 immunoreactivity was noted in 29 of 42 (69%) rectal glandular neoplasms (3 of 7 adenomas [43%] and 26 of 35 adenocarcinomas [74%]) and 9 of 18 (50%) nonneoplastic anorectal mucosal samples. In contrast, only 3 of the 11 (27%) colonic adenocarcinomas proximal to rectum were CK7 positive. Because of the relatively higher frequency of CK7 expression in rectal epithelial neoplasms, when CK7 is applied to distinguish primary colorectal versus metastatic origin, its reactivity should be interpreted with caution and should not be used as the sole evidence for excluding a rectal primary, particularly in tumors involving the rectal or pelvic region.

title: Peripheral pulmonary adenocarcinomas with bronchioloalveolar features: immunophenotypes correlate with histologic patterns.
abstract: Peripheral pulmonary adenocarcinomas (PPAs) often demonstrate a bronchioloalveolar component, with or without glandular differentiation. PPAs can be nondescript, mucinous, or show features of Type II pneumocytes. Particularly, mucinous lung carcinomas can resemble gastrointestinal metastases. Previous reports suggested that patterns of keratins 7 (K7) and 20 (K20) differ in pulmonary tumors versus enteric metastases. These studies, however, often failed to specify the precise morphotypes of PPA. Thus, we undertook this evaluation of PPAs with different histologic images. Thirty-nine cases were retrieved from institutional files; all were confirmed as primary tumors by clinicopathologic and radiographic review. Cases were classified as Type I (mucinous) bronchioloalveolar carcinoma (BAC1); Type II (nonmucinous) bronchioloalveolar carcinoma (BAC2); conventional PPA with BAC1-like areas (PPA1); or conventional PPA with BAC2-like foci (PPA2). Immunostains were performed for K7, K20, carcinoembryonic antigen, CA19-9, tumor-associated glycoprotein-72, surfactant apoprotein-A, and the c-erbB-2 peptide. BAC1 and PPA1 failed to express surfactant apoprotein-A, and BAC2 also consistently lacked K20, whereas 28% of PPA2 lesions were labeled for K20. All of the other determinants, however, were seen in variable proportions in each subgroup of PPA. Primary BAC1 and PPA1 resembled enteric adenocarcinomas immunophenotypically; on the other hand, BAC2 demonstrated a pattern of protein expression similar to that of Type II pneumocytes. PPA2s are a diverse group of neoplasms, and a subset of PPA2 does show K20 reactivity, as would be expected in metastatic enteric carcinomas. Thus, immunohistochemical data on PPAs must be interpreted carefully and only in clinicopathologic context. With respect specifically to primary pulmonary mucinous tumors, there still seems to be no uniformly reliably marker that will always allow the exclusion of metastatic enteric tumors.

title: Primary Signet-Ring Cell Carcinoma of Lung: Immunohistochemical Study and Comparison With Non-Pulmonary Signet-Ring Cell Carcinomas
abstract: Signet-ring cell carcinoma (SRCC) of lung is a rare variant of pulmonary adenocarcinoma. In view of this rarity, the question of whether an SRCC is primary pulmonary or metastatic arises frequently because the majority of SRCCs seen in lung are metastatic tumors having arisen in stomach, colon, or breast. On routine histologic examination it is difficult to distinguish between pulmonary SRCC from SRCC metastasizing from other organs. Thyroid transcription factor-1 (TTF-1) is a homeodomain-containing transcription factor that is almost exclusively expressed in thyroid and pulmonary epithelial cells. TTF-1 expression has been demonstrated in various neoplasms of lung; however, the expression of TTF-1 in SRCCs has not been investigated so far. In the present study, using an immunoperoxidase staining procedure on paraffin sections, we investigated the expression of TTF-1, cytokeratin 7, cytokeratin 20, and villin (a specific marker expressed in tumors of the digestive tract, renal proximal tubules, and hepatic bile ducts) in 32 SRCCs from various organs (17 lung, 5 breast, 5 stomach, and 5 colon). Fourteen (82.4%) of 17 pulmonary SRCCs exhibited TTF-1 positivity, whereas none of the SRCCs of other organs were positive for TTF-1. A cytokeratin profile (CK7+/CK20−) was identified in 94.1% of pulmonary SRCC, and although it differed from the profile exhibited in colonic SRCCs (CK7−/CK20+), a similar profile was seen in breast SRCCs and some SRCCs arising in the stomach. Villin was identified in 29.4% of pulmonary SRCCs and 20% (one case) arising in the breast. Although the pattern of villin immunostaining exhibited by nondigestive tract SRCCs (cytoplasmic) differed from those of digestive tract SRCCs (membranous), distinguishing between the two groups based on their pattern of immunostaining alone would be difficult. The results of this study indicate that TTF-1 is expressed in a high percentage of pulmonary SRCCs and is very specific and that TTF-1 would be extremely valuable in distinguishing pulmonary SRCCs from those arising in other organs.

title: Mucinous and nonmucinous bronchioloalveolar adenocarcinomas have distinct staining patterns with thyroid transcription factor and cytokeratin 20 antibodies.
abstract: We studied 14 mucinous and 26 nonmucinous bronchioloalveolar adenocarcinomas (BACs) with thyroid transcription factor (TTF), cytokeratin (CK) 7, CK20, and villin to characterize their staining patterns with these antibodies and identify staining differences between the neoplasms. We also stained 11 mucinous colon adenocarcinomas with the same antibodies to compare their reaction patterns with mucinous BACs. All pulmonary neoplasms were confirmed pulmonary primary BACs. Three (21%) of 14 mucinous neoplasms had weak TTF reactivity in fewer than 25% of neoplastic cell nuclei, and the other 11 (79%) were nonreactive. In contrast, 24 (92%) of 26 nonmucinonus BACs were strongly TTF reactive. Eleven mucinous BACs (79%) had CK20 reactivity in more than 25% of neoplastic cells, whereas only 1 nonmucinous BAC (4%) had reactivity in fewer than 50% of the cells. One mucinous BAC (7%) had villin reactivity in approximately 10% of the neoplastic cells. All mucinous colon adenocarcinomas were diffusely reactive with CK20 and villin. Mucinous and nonmucinous BACs have disparate staining patterns with TTF and CK20. Mucinous BACs are usually TTF nonreactive and CK20 reactive, but nonreactive with villin, which distinguishes them from mucinous colon adenocarcinomas.

title: CDX-2 Homeobox Gene Expression Is a Reliable Marker of Colorectal Adenocarcinoma Metastases to the Lungs
abstract: Lung metastases from colorectal carcinomas (CRC) can be resected with improved survival. The distinction between primary lung adenocarcinomas and metastases from CRC may sometimes be difficult, especially on cytologic specimens or small bronchoscopic biopsies. Immunohistochemistry may be of help in this setting: available markers include TTF-1 and SP-A, which are markers of lung origin, whereas there are no good markers of intestinal origin, besides cytokeratin 7 and 20 coexpression pattern, which is not very specific. The nuclear CDX-2 transcription factor, which is the product of a homeobox gene necessary for intestinal organogenesis, is expressed in normal colonic epithelia and most colorectal adenocarcinomas, and could potentially be of diagnostic usefulness. Our aim was to investigate CDX-2 immunohistochemical expression using a new monoclonal antibody and to verify if CDX-2 can be a reliable marker to identify the colorectal origin of lung metastases. CDX-2 expression was evaluated in formalin-fixed, paraffin-embedded samples of normal adult human tissues (50 samples) and in 299 surgically resected carcinomas of different origins, including 125 non-lung adenocarcinomas, 117 primary lung tumors, 5 mesotheliomas, and 52 adenocarcinomas metastatic to the lung. CDX-2 was also evaluated on a series of 20 bioptic and 10 cytologic specimens (5 cases of colorectal metastases to the lung, 5 cases of metastases from other organs, and 10 primary lung adenocarcinomas). In normal tissues CDX-2 immunoreactivity was observed only in ileal and colorectal epithelia. CDX-2 was expressed in almost all primary and metastatic CRC (88 of 90) and was never observed in primary lung tumors. CDX-2 was also expressed in a limited group of adenocarcinomas of other sites (gastric, biliopancreatic, and mucinous ovarian adenocarcinomas). CDX-2 could be easily detected in all bioptic and cytologic samples of CRC metastases. CDX-2 is a reliable, specific, and sensitive immunohistochemical marker of normal and neoplastic intestinal epithelium. CDX-2 can be easily applied to routine histologic and cytologic material and is therefore a useful marker in the differential diagnosis of primary versus metastatic adenocarcinomas in the lung, and among metastases from an unknown primary, supports intestinal origin.

title: CDX2, a Highly Sensitive and Specific Marker of Adenocarcinomas of Intestinal Origin: An Immunohistochemical Survey of 476 Primary and Metastatic Carcinomas
abstract: CDX2 is a recently cloned homeobox gene that encodes an intestine-specific transcription factor, expressed in the nuclei of epithelial cells throughout the intestine, from duodenum to rectum. While expression of CDX2 protein in primary and metastatic colorectal carcinomas has been previously documented, neither the sensitivity nor the specificity of CDX2 expression, as determined by immunohistochemistry, for colorectal adenocarcinoma has been determined. We performed an immunohistochemical survey of 476 tumors with a monoclonal antibody, CDX2–88, including 89 tumors from the colon and duodenum and 95 tumors from other gastrointestinal sites, including the esophagus, stomach, pancreatobiliary system, gastrointestinal carcinoids, and liver. CDX2 was expressed uniformly (that is, in 76–100% of tumor cells) in all but one of the evaluated colorectal and duodenal tumors. High-level expression of CDX2 was also found, however, in mucinous ovarian carcinomas and adenocarcinomas primary to the urinary bladder of which 64% and 100% were positive, respectively. Gastric, gastroesophageal, and pancreatic adenocarcinomas and cholangiocarcinomas all showed similar, heterogeneous patterns of CDX2 expression. Most tumors in each group showed CDX2 expression by a minority of cells, whereas a substantial minority of cases in each group was completely negative and a smaller minority was uniformly positive. Gastrointestinal carcinoids gave similarly varied results, but the majority (58%) was negative. Hepatocellular carcinomas showed no expression of CDX2. Only very rare examples of carcinomas of the genitourinary and gynecologic tracts, breast, lung, and head and neck showed significant levels of CDX2 expression. In this study of primary and metastatic epithelial tumors, uniform CDX2 expression is demonstrated to be an exquisitely sensitive and highly, but incompletely, specific marker of intestinal adenocarcinomas. Compared with villin, a previously described marker of GI adenocarcinomas, CDX2 demonstrated superior sensitivity and comparable specificity. CDX2 expression can be seen, however, in selected non-GI adenocarcinomas such as mucinous ovarian carcinomas and adenocarcinomas of the urinary bladder.

title: Cdx2 Protein Expression in Normal and Malignant Human Tissues: An Immunohistochemical Survey Using Tissue Microarrays
abstract: Cdx2 has been identified as a marker of colon cancer in RNA-profiling experiments. We show here that the detection of Cdx2 protein by immunohistochemistry correlates well with RNA transcript levels as detected by oligonucleotide microarrays. Using tissue microarrays containing most normal tissue types and an antibody to the Cdx2 protein, strong diffuse Cdx2 staining was only seen in the nuclei of small and large intestinal epithelium and portions of the pancreatic duct system. In tissue microarrays containing 745 cancers from many anatomic sites, colonic adenocarcinomas showed strong extensive staining in 90% of cases, with adenocarcinomas of the stomach, esophagus, and ovary (endometrioid and mucinous types) showing extensive staining in only 20–30% of cases. Other types of carcinomas showed extensive staining in only ≤1% of cases. Of 30 neuroendocrine tumors examined, carcinoids of the midgut and hindgut had the most cases with extensive staining (73% and 44%, respectively), thus paralleling the distribution of Cdx2 expression in adenocarcinomas. Cdx2 shows a limited range of expression in the spectrum of human tissues and neoplasia and thus may have utility in determining the site of origin of tumors in certain clinical situations.

title: TTF-1 protein expression in pleural malignant mesotheliomas and adenocarcinomas of the lung.
abstract: TTF-1 is a tissue-specific transcription factor expressed in the epithelial cells of thyroid and lung. This study investigates the immunohistochemical expression of TTF-1 in pleural malignant mesotheliomas (MM) and adenocarcinomas (AC) of the lung, respectively. For this purpose, 33 biopsy specimens of pulmonary AC and 24 specimens of MM were studied. TTF-1 immunoreactivity was identified in 19 of 33 cases of AC (57.5%) and in none of the 24 cases of MM. Positivity for TTF-1 was 100% specific and 57.5% sensitive for lung AC. Alternatively, negativity for TTF-1 was 57.5% specific and 100% sensitive for MM. These results suggest that TTF-1 can be favourably added to the immunohistochemical diagnostic panel for distinction between AC of the lung involving the pleura and pleural MM.

title: Is TTF1 a good immunohistochemical marker to distinguish primary from metastatic lung adenocarcinomas?
abstract: To evaluate the immunohistochemical expression of thyroid transcription factor 1 (TTF1) in primary and metastatic pulmonary adenocarcinomas, and test the diagnostic accuracy of this antibody, two surgical pathologists independently evaluated 34 cases of adenocarcinomas in the lung without clinical data and tried to distinguish between primary and metastatic cases using histological criteria exclusively. Thirteen cases were primary in the lung and 21 were metastases of extrapulmonary adenocarcinomas: 6 from the endometrium, 4 from the ovary, 3 from the colon, 2 from the kidney, 2 from the breast, 2 from the liver and 1 from the prostate. Afterward, the immunoreactivity of TTF1 in these neoplasms was evaluated and correlated with morphological and clinical data. The two pathologists were able to diagnose only 5 out of 13 cases of primary lung adenocarcinomas (sensitivity of 38.46%) and also misdiagnosed two primary malignancies as metastases. After correlation with TTF1 data, the sensitivity increased to 61.53%. The specificity of TTF1 was 100%. In conclusion, TTF1 is a highly specific marker for primary lung adenocarcinomas, and should be included in a panel of antibodies for the differential diagnosis between primary and metastatic adenocarcinomas of the lung.

title: Thyroid transcription factor-1 is a marker of lung and thyroid carcinomas.
abstract: Thyroid transcription factor-1 (TTF-1) is a tissue specific transcription factor expressed in epithelial cells of the thyroid and lung, as well as in certain areas of the brain. Recent investigations have shown that TTF-1 is also commonly present in a wide variety of thyroid and lung tumors. Because of its restrictive expression, TTF-1 is a useful immunohistochemical marker in the diagnosis of tumors of thyroid or lung origin.

title: Thyroid transcription factor‐1 is the superior immunohistochemical marker for pulmonary adenocarcinomas and large cell carcinomas compared to surfactant proteins A and B
abstract: Antibodies against the thyroid transcription factor‐1 (TTF‐1) and the surfactant proteins A and B (SPA, SPB) were compared as paraffin‐reactive immunohistochemical markers for non‐small cell carcinomas of pulmonary origin.

title: Utility of surfactant protein B precursor and thyroid transcription factor 1 in differentiating adenocarcinoma of the lung from malignant mesothelioma.
abstract: Differentiation of malignant mesothelioma from adenocarcinoma, particularly from a lung primary, remains a difficult diagnostic problem. Surfactant protein B precursor (pro-SP-B) and thyroid transcription factor 1 (ITF-1) are expressed selectively in the normal respiratory epithelium and in adenocarcinomas of the lung. In this study, we evaluated the utility of pro-SP-B and ITF-1 in distinguishing pulmonary adenocarcinomas and malignant mesotheliomas. Immunoreactivity for pro-SP-B and TTF-1 was examined in paraffin sections of 370 primary lung carcinomas (208 adenocarcinomas, 101 squamous cell carcinomas, and 61 large cell carcinomas) and 95 malignant mesotheliomas, using a pro-SP-B antiserum and a monoclonal TTF-1 antibody with a biotin-streptavidin detection system. Immunostaining for pro-SP-B was detected in 57% of adenocarcinomas, and 20% of large cell carcinomas. Immunoreactivity for TTF-1 was shown in 76% of adenocarcinomas and 26% of large cell carcinomas. Malignant mesotheliomas and squamous cell carcinomas did not stain with either antibody. The expression of pro-SP-B and TTF-1 in adenocarcinomas of the lung but not in malignant mesotheliomas shows that pro-SP-B and TTF-1 staining is useful in differentiating these neoplasms.

title: Prognostic significance of thyroid transcription factor-1 expression in both early-stage conventional adenocarcinoma and bronchioloalveolar carcinoma of the lung.
abstract: Thyroid transcription factor 1 (TTF-1) is a diagnostic immunohistochemical marker for primary pulmonary neoplasms, but its utility as a prognostic marker is not well established. Surgical specimens from 100 cases of pulmonary adenocarcinoma were retrieved from the hospital computer system, including 50 cases of conventional adenocarcinoma (CA) and 50 cases of bronchioloalveolar adenocarcinoma (BAC) (32 nonmucinous type and 18 mucinous type). Representative sections were immunostained for TTF-1. Positive immunohistochemical study was correlated with other prognostic parameters. In the CA group, strong or moderate TTF-1 expression was seen in 30 of 50 (60%) patients and was associated with significantly better survival compared with those patients having weak staining (7 cases; 14%) or negative staining (13 cases; 26%) (P <0.01; log-rank test). Spearman and Pearson's correlation showed no significant correlation between TTF-1 expression and tumor grade, size, recurrence, or vascular invasion; therefore, TTF-1 was considered an independent predictor of survival. In the BAC group, TTF-1 was strongly expressed in 34 of 50 cases (68%) and was negative in 16 of 50 cases (32%), including 14 mucinous BACs. Although TTF-1 immunoreactivity was not statistically associated with good survival in BAC patients, those patients with strong immunohistochemical expression showed a trend toward longer survival. Our results indicate that TTF-1 positivity is an independent predictor of better survival, especially in patients with CA. Mucinous and nonmucinous BACs exhibit disparate staining patterns with TTF-1, with nonmucinous BAC demonstrating greater positivity. Although nonmucinous BAC patients showing strong positive staining had longer survival, the difference was not statistically significant, which is probably related to the overall good survival of patients with early-stage BAC.

title: Expression of Thyroid Transcription Factor-1, Cytokeratin 7, and Cytokeratin 20 in Bronchioloalveolar Carcinomas: an Immunohistochemical Evaluation of 67 Cases
abstract: Distinguishing primary pulmonary adenocarcinoma from metastatic adenocarcinoma involving the lung is a common challenging task. The distinction between mucinous bronchioloalveolar carcinoma (BAC) and metastatic mucinous carcinoma of other sites, in particular, is difficult by routine histology. Immunohistochemical expression of thyroid transcription factor-1 (TTF-1), as well as cytokeratin 7 (CK 7) and cytokeratin 20 (CK 20), has proven diagnostic utility in discerning primary from metastatic neoplasms in the lung. Rigorous studies assessing the expression of these markers in BACs, particularly in regard to nonmucinous and mucinous subtypes, have not been performed. In this study, we evaluated the immunohistochemical expression of TTF-1, CK 7, and CK 20 in 67 BACs (48 nonmucinous, 12 mucinous, and 7 of mixed histology). Overall, 42 (63%) of the 67 BACs were positive for TTF-1. When stratified according to subtype, all 12 mucinous BACs were observed to be TTF-1 negative. This trend toward absence of TTF-1 expression in mucinous areas was also maintained among tumors with mixed histology. Sixty-three (94%) of 67 BACs were CK 7 positive, with no differences in expression observed upon subtype stratification. Three cases were noted to be positive for CK 20; all exhibited mucinous morphology. These results indicate that in contrast to the immunophenotypic profile exhibited by most pulmonary neoplasms, mucinous BACs are TTF-1 negative and may express CK 20. This suggests that in the context of differentiating mucinous BACs from extrapulmonary mucinous tumors metastatic to the lung, evaluation of TTF-1 and CK 20 expression may have limited diagnostic utility.

title: The transcription factor TTF-1 is expressed at the onset of thyroid and lung morphogenesis and in restricted regions of the foetal brain.
abstract: TTF-1, a homeodomain-containing transcription factor, which is required for the specific expression of the thyroglobulin and thyroperoxidase gene promoters in differentiated thyroid cell lines, is expressed at the very beginning of rat thyroid differentiation. TTF-1 mRNA is detected in the endodermal cells of the thyroid rudiment in the rat embryo and precedes the expression of the two known target genes by 5 days. No delay is observed between the appearance of TTF-1 mRNA and protein, which shows a clear nuclear localization. In the adult thyroid, TTF-1 is present only in the endoderm-derived follicular cells. Two additional domains of expression of TTF-1 have been observed, the lung and restricted areas of the brain. In the lung, TTF-1 mRNA and protein are also present at the earliest stages of differentiation and are later confined to the bronchial epithelium. In the brain, TTF-1 appears to be restricted to structures of diencephalic origin, including the developing neurohypophysis. The early detection of TTF-1 in the endodermal cells of the thyroid and lung anlage and in restricted neuroblast populations indicates that TTF-1 may have a role in cell determination in these three systems and that additional mechanisms may be involved in the activation of thyroid-specific gene expression.

title: Cytokeratin 7 and Cytokeratin 20 Expression in Epithelial Neoplasms: A Survey of 435 Cases
abstract: Cytokeratin 7 (CK 7) and cytokeratin 20 (CK 20) are low molecular weight cytokeratins. Their anatomic distribution is generally restricted to epithelia and their neoplasms. We surveyed 435 epithelial neoplasms from various organ systems by immunohistochemistry using CK 7 and CK 20 monoclonal antibodies. Expression of CK 7 was seen in the majority of cases of carcinoma, with the exception of those carcinomas arising from the colon, prostate, kidney, and thymus; carcinoid tumors of the lung and gastrointestinal tract origin; and Merkel cell tumor of the skin. The majority of cases of squamous cell carcinoma of various origins were negative for CK 7, except cervical squamous cell carcinoma, in which 87% of cases were positive. Approximately two thirds of cases of malignant mesothelioma were CK 7-positive. CK 20 positivity was seen in virtually all cases of colorectal carcinomas and Merkel cell tumors. CK 20-positive staining was also observed in cases of pancreatic carcinomas (62%), gastric carcinoma (50%), cholangiocarcinomas (43%), and transitional cell carcinomas (29%). The expression of CK 20 was virtually absent in carcinomas from other organ systems and in malignant mesothelioma. CK 7- and CK 20-negative epithelial neoplasms included adrenal cortical carcinoma, germ cell tumor, prostate carcinoma, renal cell carcinoma, and hepatocellular carcinoma.

title: Villin, cytokeratin 7, and cytokeratin 20 expression in pulmonary adenocarcinoma with ultrastructural evidence of microvilli with rootlets.
abstract: Villin (V) is a glycoprotein of microvilli associated with rootlet formation. Most colonic adenocarcinomas have a V positive (+), cytokeratin (CK) 20 (+), CK7-negative (-) immunophenotype; most lung adenocarcinomas have a CK20(-), CK7(+) immunophenotype. The reports of villin immunoreactivity in lung adenocarcinoma range from 6% to 68% in studies using various fixations and varied anti-villin antibodies. Some lung adenocarcinomas have microvilli with rootlets leading to possible diagnostic confusion with metastatic colonic adenocarcinoma to lung. Nine primary lung adenocarcinomas with rootlets on ultrastructure (including four bronchioloalveolar carcinomas [BAC]), four metastatic lung adenocarcinomas with rootlets, nine metastatic colon adenocarcinomas to lung, and 10 randomly selected lung adenocarcinomas without rootlets (including five BAC), were immunostained with monoclonal antibodies to villin (1D2C3), CK7 (OV-TL12/30), and CK20 (Ks20.8) using a streptavidin peroxidase technique with heat-induced epitope retrieval. All primary lung adenocarcinomas with rootlets were CK7(+) CK20(-), and six of nine (67%) were V(+). Cytoplasmic villin positivity occurred in a diffuse--five of nine (56%), focal--two of nine (22%), or brush border pattern--two of nine (22%). Two of four metastatic lung adenocarcinomas with rootlets were V(+). One metastatic lung adenocarcinoma had a CK7(+), CK20(+), V(-) phenotype. All metastatic colonic adenocarcinomas were V(+), CK20(+), CK7(-), and 1 of 10 (10%) lung adenocarcinomas without rootlets was V(+), and all 10 were CK20(-), and CK7(+). In summary, villin positivity is more common in lung adenocarcinoma with rootlets (67%) than those without rootlets (10%). AU primary lung adenocarcinomas were CK7(+), CK20(-). The combination of villin, CK 7, and CK 20 is helpful in differentiating metastatic colon adenocarcinoma from lung adenocarcinoma with rootlets.

title: Unique expression patterns and alterations in the intestinal protein villin in primary and metastatic pulmonary adenocarcinomas
abstract: The identification of markers that distinguish primary pulmonary adenocarcinomas from pulmonary adenocarcinomas secondary to the digestive tract would be clinically important. Villin, a specific marker in digestive‐tract malignancies, was evaluated in 57 pulmonary adenocarcinomas, six samples of proximal bronchial tissue, and five metastatic pulmonary adenocarcinomas (three colon and two esophageal adenocarcinomas) by using immunohistochemical and molecular analyses. Villin was expressed in 31.6% (18 of 57) of the pulmonary adenocarcinomas and showed either a diffuse cytoplasmic pattern (10.5%) or a primary cytoplasmic pattern with minor brush‐border staining (21.1%). However, none of those samples demonstrated the primary brush‐border staining pattern that was characteristic of all five of the metastatic digestive‐tract adenocarcinomas. There was a significant difference in the positive brush‐border staining pattern between the primary and metastatic pulmonary adenocarcinomas (P < 0.002). Villin protein was expressed in bronchial epithelial cells, and villin mRNA was detected by reverse transcription–polymerase chain reaction. Northern analysis demonstrated 3.5‐ and 2.7‐kb villin mRNAs in villin protein–positive tumors, but villin mRNA was not detected in non‐tumorous lung tissue, indicating the transcriptional upregulation of villin in lung tumors. An additional smaller‐sized mRNA (1.8 kb) was observed in six of 10 pulmonary adenocarcinomas and in the bronchoalveolar carcinoma cell line A549. Two small villin mRNAs were cloned from the cell line A549 and were found to represent an alternatively spliced (exon 8–exon 14) 1.85‐kb mRNA and a 1.8‐kb mRNA that was missing a portion of the 5′ region (exon 1–exon 9) of the native villin mRNA. These studies demonstrated that the pattern of villin expression and the presence of altered villin mRNAs may be useful markers for pulmonary adenocarcinomas as well as provide support for the potential origin of villin‐expressing tumors from bronchial epithelial cells.  1998.

title: Differences in expression of homeobox transcription factors in proximal and distal human small intestine.
abstract: Different digestive enzymes and transporters are present in the duodenum, jejunum, and ileum, but the factors determining region-specific gene expression are not yet understood. Homeobox transcription factors are important in defining gradients of cellular differentiation. The aim of this study was to investigate whether their expression differs between proximal (duodenal) and distal (ileal) regions of human small intestine.



Intestinal RNA was prepared from surgical patients, and reverse-transcription polymerase chain reactions (PCRs) performed with mixed sequence oligonucleotide primers based on conserved regions. PCR products were identified by cloning and sequencing. Transcript abundance was determined by Northern blotting.



The human homologues were identified as Cdx-1, Cdx-2 (or Cdx-3), Pdx-1 (previously named Islet/duodenal homeobox [Idx]-1, Ipf-1, or Stf-1), and 13 human homeodomain cluster genes, including HOXB3, HOXB4, and HOXA6. The relative abundance of some of these differed between duodenum and ileum. Pdx-1 transcripts were found only in duodenum, Cdx-2, Cdx-1, and HOXB3 were readily detectable in both regions, with Cdx-1 having a more marked distal expression.



Many homeobox genes are expressed in human adult small intestinal mucosa, and some are found predominantly in one region.

title: Loss of CDX2 expression and microsatellite instability are prominent features of large cell minimally differentiated carcinomas of the colon.
abstract: Most large bowel cancers are moderately to well-differentiated adenocarcinomas comprised chiefly or entirely of glands lined by tall columnar cells. We have identified a subset of poorly differentiated colon carcinomas with a distinctive histopathological appearance that we term large cell minimally differentiated carcinomas (LCMDCs). These tumors likely include a group of poorly differentiated carcinomas previously described by others as medullary adenocarcinomas. To better understand the pathogenesis of these uncommon neoplasms, we compared molecular features of 15 LCMDCs to those present in 25 differentiated adenocarcinomas (DACs) of the colon. Tumors were examined for alterations commonly seen in typical colorectal carcinomas, including increased p53 and beta-catenin immunoreactivity, K-ras gene mutations, microsatellite instability, and loss of heterozygosity of markers on chromosomes 5q, 17p, and 18q. In addition, tumors were evaluated by immunohistochemistry for CDX2, a homeobox protein whose expression in normal adult tissues is restricted to intestinal and colonic epithelium. Markedly reduced or absent CDX2 expression was noted in 13 of 15 (87%) LCMDCs, whereas only 1 of the 25 (4%) DACs showed reduced CDX2 expression (P < 0.001). Nine of 15 (60%) LCMDCs had the high-frequency microsatellite instability phenotype, but only 2 of 25 (8%) DACs had the high-frequency microsatellite instability phenotype (P = 0.002). Our findings provide support for the hypothesis that the molecular pathogenesis of LCMDCs is distinct from that of most DACs. CDX2 alterations and DNA mismatch repair defects have particularly prominent roles in the development of LCMDCs.