1267 Expression of her-2/NEU EGFR, hormone receptors, cathepsyn-D and ploidy in normal and neoplastic GI tract tissues

Six biochemical parameters, recognized as being prognostic factors in breast cancer, were evaluated on fresh samples of human GI tract tumors to better define the biology and natural history of such neoplasms. Levels of expression of HER-2/neu oncogene and epidermal growth factor receptor (EGFr) protein products, ER, PgR, cathepsin-D and ploidy were determined in 16 gastric and 39 colorectal tumors and compared with normal samples from the same subjects. In 56% of gastric, 61% of colon and 35% of rectum carcinomas HER-2/neu gene product p185 was significantly overexpressed as compared to normal tissues. On the contrary colon and rectum tumors expressed significantly lower levels of EGFr than normal in 60% of cases. Very low levels of ER and PgR were detected in all the samples (normal and malignant) tested. 75% of tumour tissues showed a significant higher cathepsin-D content compared to the respective normal sample while an aneuploid DNA profile was documented in 72% of neoplasms. Overall, change of the markers evaluated seems to be a specific phenomenon of certain GI carcinomas. Higher EGFR levels in normal than malignant tissues suggest that EGFR can be implicated in the process of growth and differentiation of the normal gastrointestinal mucosa. Further studies on a larger number of cases along with an adequate follow-up of patients are needed to define the role of these markers in the pathogenesis of GI tract neoplasms and its prognostic significance when considered together with other major risk factors.