Patterns of PIK3CA alterations in familial colorectal and endometrial carcinoma.
While the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway is known to be activated in multiple sporadic cancers, the role of this pathway in familial tumors is mostly unknown. We searched for alterations in the catalytic domain of PI3K (PIK3CA), PTEN and KRAS, all of which may contribute to PI3K/AKT pathway activation, in a total of 160-familial colorectal (CRC) and endometrial carcinomas (EC), stratified by the presence vs. absence of germline mutations in DNA mismatch repair (MMR) genes. PIK3CA alterations (consisting of point mutations or low-level amplification, which were mutually exclusive with 1 exception) occurred in 10/70 (14%) of CRCs and 19/90 (21%) of ECs. Within ECs, amplification was significantly associated with the subgroup lacking germline mutations in MMR genes (familial site-specific endometrial cancer) (p = 0.015). Decreased or lost PTEN expression was characteristic of endometrial tumourigenesis (51/81, 63%, in EC compared with 24/62, 39%, in CRC, p = 0.004) and KRAS mutations of colorectal tumourigenesis (19/70, 27% in CRC vs. 9/89, 10%, in EC, p = 0.006) regardless of the MMR gene mutation status. PIK3CA alterations frequently coexisted with PTEN or KRAS changes. Combined with published studies on sporadic tumors, our data broaden the understanding of the role for PI3K pathway genes in human tumorigenesis.
Ollikainen
Miina
M
Department of Medical Genetics, University of Helsinki, Helsinki, Finland.
Gylling
Annette
A
Puputti
Marjut
M
Nupponen
Nina N
NN
Abdel-Rahman
Wael M
WM
Butzow
Ralf
R
Peltomäki
Päivi
P
D000368:Aged; D058534:Class I Phosphatidylinositol 3-Kinases; D015179:Colorectal Neoplasms / Q000235:genetics*; D016889:Endometrial Neoplasms / Q000235:genetics*; D005260:Female; D005784:Gene Amplification; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics; D008875:Middle Aged; D009154:Mutation; D051059:PTEN Phosphohydrolase / Q000235:genetics; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics*; D018807:Polymorphism, Single-Stranded Conformational; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D020133:Reverse Transcriptase Polymerase Chain Reaction; D018631:ras Proteins / Q000235:genetics
C117307:KRAS protein, human; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D019869:Phosphatidylinositol 3-Kinases; D058534:Class I Phosphatidylinositol 3-Kinases; C484760:PIK3CA protein, human; C446603:TPTE protein, human; D051059:PTEN Phosphohydrolase; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins