Comprehensive genomic sequencing detects important genetic differences between right-sided and left-sided colorectal cancer

Yoshifumi Shimada, Hitoshi Kameyama, Masayuki Nagahashi, Hiroshi Ichikawa, Yusuke Muneoka, Ryoma Yagi, Yosuke Tajima, Takuma Okamura, Masato Nakano, Jun Sakata, Takashi Kobayashi, Hitoshi Nogami, Satoshi Maruyama, Yasumasa Takii, Tetsu Hayashida, Hiromasa Takaishi, Yuko Kitagawa, Eiji Oki, Tsuyoshi Konishi, Fumio IshidaShin ei Kudo, Jennifer E. Ring, Alexei Protopopov, Stephen Lyle, Yiwei Ling, Shujiro Okuda, Takashi Ishikawa, Kohei Akazawa, Kazuaki Takabe, Toshifumi Wakai

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

Abstract

Objectives: Anti-epidermal growth factor receptor (EGFR) therapy has been found to be more effective against left-sided colorectal cancer (LCRC) than rightsided colorectal cancer (RCRC). We hypothesized that RCRC is more likely to harbor genetic alterations associated with resistance to anti-EGFR therapy and tested this using comprehensive genomic sequencing. Materials and methods: A total of 201 patients with either primary RCRC or LCRC were analyzed. We investigated tumors for genetic alterations using a 415-gene panel, which included alterations associated with resistance to anti-EGFR therapy: TK receptors (ERBB2, MET, EGFR, FGFR1, and PDGFRA), RAS pathway (KRAS, NRAS, HRAS, BRAF, and MAPK2K1), and PI3K pathway (PTEN and PIK3CA). Patients whose tumors had no alterations in these 12 genes, theoretically considered to respond to anti-EGFR therapy, were defined as "all wild-type", while remaining patients were defined as "mutant-type". Results: Fifty-six patients (28%) and 145 patients (72%) had RCRC and LCRC, respectively. Regarding genetic alterations associated with anti-EGFR therapy, only 6 of 56 patients (11%) with RCRC were "all wild-type" compared with 41 of 145 patients (28%) with LCRC (P = 0.009). Among the 49 patients who received anti-EGFR therapy, RCRC showed significantly worse progression-free survival (PFS) than LCRC (P = 0.022), and "mutant-type" RCRC showed significantly worse PFS compared with "all wild-type" LCRC (P = 0.004). Conclusions: RCRC is more likely to harbor genetic alterations associated with resistance to anti-EGFR therapy compared with LCRC. Furthermore, our data shows primary tumor sidedness is a surrogate for the non-random distribution of genetic alterations in CRC.

Original languageEnglish
Pages (from-to)93567-93579
Number of pages13
JournalOncotarget
Volume8
Issue number55
DOIs
Publication statusPublished - 01-11-2017

All Science Journal Classification (ASJC) codes

  • Oncology

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