title: Phosphatidylinositol-3-kinase pathway aberrations in gastric and colorectal cancer: meta-analysis, co-occurrence and ethnic variation.
abstract: Inhibition of the phosphatidylinositol-3-kinase (PI3K) signaling pathway is a cancer treatment strategy that has entered into clinical trials. We performed a meta-analysis on the frequency of prominent genetic (PIK3CA mutation, PIK3CA amplification and PTEN deletion) and protein expression (high PI3K, PTEN loss and high pAkt) aberrations in the PI3K pathway in gastric cancer (GC) and colorectal cancer (CRC). We also performed laboratory analysis to investigate the co-occurrence of these aberrations. The meta-analysis indicated that East Asian and Caucasian GC patients differ significantly for the frequencies of PIK3CA Exon 9 and 20 mutations (7% vs. 15%, respectively), PTEN deletion (21% vs. 4%) and PTEN loss (47% vs. 78%), while CRC patients differed for PTEN loss (57% vs. 26%). High study heterogeneity (I(2) > 80) was observed for all aberrations except PIK3CA mutations. Laboratory analysis of tumors from East Asian patients revealed significant differences between GC (n = 79) and CRC (n = 116) for the frequencies of PIK3CA amplification (46% vs. 4%) and PTEN loss (54% vs. 78%). The incidence of GC cases with 0, 1, 2 and 3 concurrent aberrations was 14%, 52%, 27% and 8%, respectively, while for CRC it was 10%, 60%, 25% and 4%, respectively. Our study consolidates knowledge on the frequency, co-occurrence and clinical relevance of PI3K pathway aberrations in GC and CRC. Up to 86% of GC and 90% of CRC have at least one aberration in the PI3K pathway, and there are significant differences in the frequencies of these aberrations according to cancer type and ethnicity.
authors: Cancer Science Institute of Singapore, National University of Singapore, Singapore.
authors: Mei-Ling
authors: ML
authors: Chong
authors: Marie
authors: M
authors: Loh
authors: Bhavin
authors: B
authors: Thakkar
authors: Brendan
authors: B
authors: Pang
authors: Barry
authors: B
authors: Iacopetta
authors: Richie
authors: R
authors: Soong
mesh_terms: D058534:Class I Phosphatidylinositol 3-Kinases; D015179:Colorectal Neoplasms / Q000208:ethnology / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D006801:Humans; D009154:Mutation; D051059:PTEN Phosphohydrolase / Q000235:genetics; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics* / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D013274:Stomach Neoplasms / Q000208:ethnology / Q000235:genetics* / Q000401:mortality / Q000473:pathology
chemical_list: D019869:Phosphatidylinositol 3-Kinases; D058534:Class I Phosphatidylinositol 3-Kinases; C484760:PIK3CA protein, human; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human
keywords: PI3K; PI3K inhibitor; colorectal cancer; gastric cancer; meta-analysis; mutation