Abstract 5278: Mutation in protein tyrosine phosphatase receptor type K (PTPRK) enhances progression of colon cancer through WNT signaling

Abstract

Abstract Recent comprehensive genome analyses revealed the accumulation of genetic alterations in colorectal cancers (CRCs). However, it is still unknown which genetic alterations are closely associated with certain phenotype of CRCs, such as tumors with highly invasive character regardless of its small size. Here we examined the small invasive CRCs using high-throughput sequencing in order to clarify the common molecular features in those CRCs. Seven small invasive CRCs (types 0-IIa+IIc or 0-Is+IIc, less than 20mm in diameter and with submucosal massive invasion) were examined by exon sequencing. Seven thousands six variants (SNVs and indels) were detected. Among them, PTPRK was frequently mutated (3 cases, 43%; 1 nonsense and 2 missense mutations). We further examined public database (TCGA and COSMIC) and found that 50 of 617 (8.17%) CRCs contain PTPRK mutation. Those cases are frequent in proximal colon, extensively methylated (CIMP-H), microsatellite instability-high (MSI-H) and pathologically mucinous type. Consistent with clinical behavior, invasion assay in CRC cell lines revealed that CRCs with PTPRK domain D1 mutation showed high invasiveness via WNT signaling activity. These data indicate that PTPRK domain D1 mutation contributes to the invasiveness and progression of proximal CRCs, especially CIMP-H and MSI-H cases. Citation Format: Masayuki Tojo, Kazuo Konishi, Keiko Shinjo, Fumiharu Ohka, Keisuke Katushima, Akira Hatanaka, Norihisa Ichimura, Hisako Nozawa, Tomoe Shimazaki, Hitoshi Yoshida, Yutaka Kondo. Mutation in protein tyrosine phosphatase receptor type K (PTPRK) enhances progression of colon cancer through WNT signaling. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5278. doi:10.1158/1538-7445.AM2015-5278