Association of genetic variants in plastin family genes with tumor recurrence in stage II/III colon cancer.
e14031 Background: Plastins belong to a subclass of actin-binding proteins known as actin bundling proteins. Plastins family constitute of two isoforms in human as T-plastin (PLS3) and L-plastin (LCP1). Recent in vitro and in vivo studies found plastin genes are overexpressed in colon cancer cells and can lead to increased proliferation, invasion and metastasis. Here we tested the hypothesis whether potential functional tagging polymorphisms in PLS3 (rs6643869, rs5987947, rs2522188) and LCP1 (rs4941543, rs1409429, rs11342) may predict tumor recurrence in adjuvant colon cancer patients. Methods: Either blood or FFPE tissue specimens were obtained from 234 patients (107 females and 127 males; median age 59 years (range 22–78 years)) with stage II (105 patients) or III (129 patients) colon cancer at the University of Southern California/Norris Comprehensive Cancer Center. The median follow-up was 4.4 years. PLS3 and LCP1 SNPs were determined by PCR-RFLP or PCR-based direct sequence. The primary endpoint of the study was time to tumor recurrence (TTR). Results: In univariable analysis, PLS3 rs6643869 and LCP1 rs4941543 were significantly associated with time to tumor recurrence (TTR). Patients with PLS3 AA genotype had shortest median TTR 3.2 years (95% C.I: 1.5-10.7) compared to those with AG or GG genotype, which had median TTR 9.4 years (95% C.I: 5.7-12.2) (p=0.012, log-rank test). Patients with LCP1 CC genotype had longer median TTR 10.7 years (95% C.I: 5.7-16.8+) compared to those with CT and TT genotypes, which had shorter median TTR 4.9 years (95% C.I: 1.4-9.0+)(p=0.040, log-rank test). PLS3 rs6643869 remained significant in the multivariate Cox regression model adjusted by stage and type of adjuvant therapy and stratified by race (p=0.021). Conclusions: Our preliminary results demonstrated that polymorphisms in plastin family genes PLS3 and LCP1 might be potential molecular markers to predict TTR in adjuvant colon cancer. Further large and biomarker embedded trial needed to confirm our findings.