BMC Cancer 2004, 4:78 http://www.biomedcentral.com/1471-2407/4/78 FFoiguurridee4ntified antigen sequences with partial homology to reverse transcriptase homolog Four identified antigen sequences with partial homology to reverse transcriptase homolog. Peptide sequence is reported in single-letter code. Identical amino acids in the selected clones and reverse transcriptase homolog are represented by a dash. These clones were isolated from libraries of different origin. Clones T9-21 and T9-27, isolated from solid tumor library, had significantly high frequency of reactivity with sera from breast cancer patients. template. It has been previously shown [18], by compar- ing the expression level of target genes in SMART PCR- amplified cDNAs and their corresponding total RNAs, that SMART cDNA accurately reflects gene expression pat- terns found in total RNA. We normalized the panel of cDNAs from ten different breast carcinomas, one metastasized lymph node, normal breast, normal testis and peripheral blood lymphocytes from healthy donors, by PCR amplification of a housekeeping gene, β-actin (Figure 5). Three of the identified antigens, fucosyltrans- ferase (T6-7), Zinc finger protein 258 (T11-6), and p53- binding protein (T1-52) [6], were ubiquitously expressed in all the tumor and normal tissue samples tested (Figure 5A). Some of the antigens, T5-15 (KIAA1735), T5-13 (Sos1), T11-5 (hypothetical protein MGC4170) were found to be downregulated in many tumors (Figure 5B). T11-9 (hypothetical protein AF225417) was overexpressed in 50% of the primary tumors and the unique metastasized lymph node tested. T11-3 (trap ankyrin repeat) was overexpressed in most of the tumors Page 6 of 10 (page number not for citation purposes)