OFP-08-003 ERCC1, p16 and ki-67 immunohistochemical expression as predictive and prognostic markers in head and neck squamous cell carcinoma treated with platin-based induction chemotherapy H. Roussel * , M. Housset, H. Tournat, P. Ravel, S. Hans, C. Badoual * HEGP, Dept. de Anatomie-Pathologie, Paris, France Objective: ECC1 enzyme has been associated with resistance to platinum-based chemotherapy. The purpose of this study was to evaluate the role of ERCC1 expression with p16 and Ki-67 as predictive and prognostic markers in the response to platin-based induction chemotherapy in patients with head and neck carcinoma (HNSCC). Method: 208 patients treated from 2000 to 2006 by an induction chemotherapy regimen for HNSCC were included retrospectively. We assessed response to treatment, progression-free survival (PFS) and overall survival (OS). Results: 68 % and 81.5 % of HNSCC showed low expression of 8 F1 and FL297 ERCC1. No correlation was found between the two clones (p=0.1). In the 129 patients treated with cisplatin-5FU chemotherapy, a low expression of 8 F1 ERCC1 was associated with a better response (p=0.027). Over expression of p16, (34.5 % of cancers of the oropharynx) was correlated with a better OS (p=0.0007) and a better PFS (p=0.01). Conclusion: These results suggest that ERCC1 expression might be a useful predictive marker of HNSCC in patients treated by cisplatin-based chemotherapy. The 8 F1 ERCC1 clone appears to be the best for immunohistochemistry. Our study confirms the prognostic value of the over expression of p16 in carcinoma of the oropharynx. Objective: Tumor-stroma ratio or proportion of tumor (PT) has been presented as a prognostic factor in colorectal and breast adenocarcinomas, but there is no information about squamous cell carcinomas (SCC) and laryngeal carcinomas in particular. Method: Eighty-five laryngeal carcinoma cases were included in this series. Five digital images of the tumor sections were obtained (H&Ex20). Percentage of epithelial tumor component was determined by software allowing the pathologist's selection of tiny areas as carcinomatous and stromal region for statistical analysis as a prognostic marker. Results: Median follow up was 48 months (range 3-194). The mean PT was (48,63+18,18) . There was no difference for PT when tumor grade and stage were considered. Although statistically insignificant, the mean PT was the lowest (37,46+12,49) for subglottic carcinomas and cases with perinodal invasion (44,72+20,23), and highest in pN0 cases (50,05+17,34) but there was no statistical significance. The over all and disease free survival analysis did not reveal significance for PT. Only pathological stage was an independent factor for over all survival (p=0,08).