569P - The location of colorectal cancer (right- vs. left-sided colon and rectum) affects the prevalence of BRAF V600E, non-V600E and PIK3CA mutations: a...

Date 08 October 2016
Event ESMO 2016 Congress
Session Poster Display
Topics Colon and Rectal Cancer
Presenter Hiroya Taniguchi
Citation Annals of Oncology (2016) 27 (6): 149-206. 10.1093/annonc/mdw370
Authors H. Taniguchi1, K. Uehara2, H. Nakayama3, G. Nakayama4, T. Takahashi5, Y. Nakano6, H. Matsuoka7, S. Utsunomiya8, E. Sakamoto9, Y. Mori10, K. Komori11, M. Tajika12, K. Muro1, Y. Yatabe13
  • 1Department Of Clinical Oncology, Aichi Cancer Center Hospital, 464-8681 - Nagoya/JP
  • 2Department Of Surgical Oncology, Nagoya University, Graduate School of Medicine, Nagoya/JP
  • 3Department Of Surgery, National Hospital Organization, Nagoya Medical Center, Nagoya/JP
  • 4Department Of Gastroenterological Surgery, Nagoya University, Graduate School of Medicine, Nagoya/JP
  • 5Department Of Surgery, Tosei General Hospital, Seto/JP
  • 6Department Of Medical Oncology, Japanese Red Cross Nagoya First Hospital, 464-8681 - Nagoya/JP
  • 7Surgery, Fujita Health University, Toyoake/JP
  • 8Deparment Of Medical Oncology, Kainan Hospital, Yatomi-shi/JP
  • 9Department Of Surgery, Japanese Red Cross Nagoya Daini Hospital, Nagoya/JP
  • 10Department Of Gastroenterology And Metabolism, Nagoya City University, Nagoya/JP
  • 11Department Of Gatsroenterological Surgery, Aichi Cancer Center Hospital, 464-8681 - Nagoya/JP
  • 12Depaerment Of Endoscopy, Aichi Cancer Center Hospital, 4648681 - Nagoya/JP
  • 13Department Of Clinical Oncologydepartment Of Pathology And Molecular Diagnostics, Aichi Cancer Center Hospital, 464-8681 - Nagoya/JP



Primary tumor location is an important predictive factor for KRAS/NRAS wild-type colorectal cancer treated with anti-EGFR therapy. BRAF and PIK3CA mutations are also known to affect a response in anti-EGFR therapy. However, the relationship between the prevalence of BRAF/PIK3CA mutations and the location of the primary site is still unclear.


We prospectively collected tumor samples and clinical data from colorectal cancer patients in 14 hospitals and investigated KRAS/NRAS/BRAF/PIK3CA gene mutations, including 33 types of BRAF non-V600E mutations, using a PCR-based multiplex kit.


As of April 30, 2015, a total of 545 CRC patients were enrolled, and 313 patients (57%) revealed KRAS/NRAS wild-type cancer. Patient characteristics included: median age, 65 (range, 30–90); male/female, 60%/40%; clinical stage I-III/IV, 15%/85%; and location of primary site, right-sided colon/left-sided colon/rectum, 23%/30%/47%. The prevalence of BRAF V600E/BRAF non-V600E/PIK3CA mutations were 10.1%, 4.7% and 5.9%, respectively. The detected BRAF non-V600E mutations were G466E, G469A, N581T, D594G, T599_V600insT, V600R, K601E and K601N. All mutations were mutually exclusive. In RAS wild-type cancer patients, BRAF/PIK3CA mutations were more frequent in female (p = 0.0029), right-sided (p = 0.0001) and peritoneal metastasis (p = 0.0016) cases and less frequent in cases presenting liver metastasis (p = 0.0041). In RAS wild-type right-sided cancers, the prevalence of BRAF V600E/ BRAF non-V600E/PIK3CA mutations were 31.7%, 8.1% and 19.2%, while in left-sided colon and rectum cancers, they were 4.6%, 2.5% and 3.6%, respectively.


More than half of RAS wild-type right-sided colon cancer patients have BRAF/PIK3CA mutations, including BRAF non-V600E. The existence of these mutations may affect anti-EGFR efficacy between right- and left-sided colorectal cancers.

Clinical trial identification

Legal entity responsible for the study



Aichi Cancer Network


All authors have declared no conflicts of interest.