P-0173 Thymidilate Synthase (TS) and Excision Repair Complementation Group 1 (ERCC1) Status And Clinicopathologic Factors in Gastro-Intestinal Cancer

Abstract

ABSTRACT Introduction Gastro-Intestinal (GI) cancers are the most common cancer types and leading cause of cancer death in Iran. Genetic abnormalities in TS and ERCC1 have seen in GI cancers frequently and associated to chemotherapy response. The aim of this study was evaluation of TS and ERCC1 abnormalities in Iranian patients with GI cancers and relationship between them and clinical and pathological characteristics. Methods Seventy patients with different type of GI cancers including esophageal, gastric and colorectal cancers were selected. cDNA was derived from paraffin-embedded tumor (FFPE) specimens to determine TS and ERCC1 mRNA expression relative to the beta –actin as a reference gene using fluorescence –based, real-time reverse transcriptase polymerase chain reaction (RT-PCR). Clinical and pathologic factors including age, sex, tumor site, grade, LVI, PNI, T and N staging also were recorded. Results Totally 70 patients with mean age 58.54 (25 to 82) were evaluated that 18 (25.7%) of them were female and 52 (74.3%) were male, also 27 (38.6%) had upper GI (esophago-gastric) and 43 (61.4%) had lower GI (Colorectal) cancer. Most of the patients had advanced T (80%) and LN+ (60%) disease. Frequency of ERCC1+ was 43% that was not significant difference according to upper or lower GI site (44% vs. 42%, p=0.832). Frequency of TS+ was 27% that although had difference according to upper or lower GI site (38% vs. 21%) but it was not significant (p=0.140). Considering TS and ERCC1 together, 33 (47%) were TS and ERCC1 negative, 25 (36%) TS or ERCC1 positive and 12(17%) TS and ERCC1 positive. There was no significant difference based on site between three category (p=0.379). In comparison of TS and ERCC1 with different clinical (age: upper or lower than 59 and sex: male or female) and pathologic (T stage: T1T2 versus T3T4 and N stage: positive or negative) were not found significant differences. Conclusion ERCC abnormalities are more frequent in GI cancer than TS. TS abnormalities in contrast to ERCC1 are detected more in upper GI cancers than lower GI. There is not any correlation between TS and ERCC1 abnormalities and different clinical and pathologic factors.