29 Background: Gastric cancer is the 2nd leading cause of cancer mortality globally. A small number of studies reported that low TS and ERCC1 mRNA levels are associated with improved survival, and may be important as prognostic factors. Methods: Intratumoral gene expression levels were assessed using laser-captured micro-dissection and quantitative Real-Time PCR on formalin fixed paraffin embedded tumor samples from 22 gastric adenocarcinomas. A retrospective chart review was performed to measure clinical parameters. Primary objectives were to determine the range of expression of TS, ERCC1, and HER2, and to investigate if these biomarkers are predictive of survival. Results: TS, ERCC1, and HER2 median expression levels using RT-PCR were 3.56, 1.54, and 0.085, respectively. Median OS was 62 months. Subjects with low TS trended towards improved survival (92 months vs. 34 months, p: 0.17), as did subjects with low ERCC1 (92 months vs. 55 months, p: 0.44). There was no association between HER2 expression and OS. All subjects had HER2 levels below 0.55. With regard to treatment, 90.9% of patients received platinum-based chemotherapy and 4.5% received HER2-guided therapy. Conclusions: Our results are consistent with prior reports that associate low TS and low ERCC1 with improved OS, and may imply prognostic significance. Although these trends did not reach statistical significance, they are consistent with prior studies. Further molecular studies are needed to better assess the utility of these markers as prognostic indicators. There was no clear trend between HER2 levels and OS, most likely because all subjects had low HER2 levels. However, as accurate determination of HER2 expression is becoming increasingly important in the management of gastric cancer patients, further research into the degree of concordance between RT-PCR assessment and FISH assessment of HER2 gene amplication is warranted. Overall, more molecular studies are needed to better stratify this disease into subtypes, and identify new drug targets for chemo-resistant subtypes.
Evaluation of the prognostic value of CBXs in gastric cancer patients