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KRAS (but not BRAF ) mutations in ovarian serous borderline tumour are associated with recurrent low‐grade serous carcinoma
Author(s) -
Tsang Yvonne T,
Deavers Michael T,
Sun Charlotte C,
Kwan SuetYan,
Kuo Eric,
Malpica Anais,
Mok Samuel C,
Gershenson David M,
Wong KwongKwok
Publication year - 2013
Publication title -
the journal of pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.964
H-Index - 184
eISSN - 1096-9896
pISSN - 0022-3417
DOI - 10.1002/path.4252
Subject(s) - kras , sanger sequencing , serous fluid , mutation , medicine , ovarian carcinoma , massive parallel sequencing , ion semiconductor sequencing , cancer research , oncology , dna sequencing , ovarian cancer , biology , cancer , gene , genetics , colorectal cancer
AbstractBRAF and KRAS mutations in ovarian serous borderline tumours ( OSBTs ) and ovarian low‐grade serous carcinomas ( LGSCs ) have been previously described. However, whether those OSBTs would progress to LGSCs or whether those LGSCs were developed from OSBT precursors in previous studies is unknown. Therefore, we assessed KRAS and BRAF mutations in tumour samples from 23 recurrent LGSC patients with a known initial diagnosis of OSBT . Paraffin blocks from both OSBT and LGSC samples were available for five patients, and either OSBTs or LGSCs were available for another 18 patients. Tumour cells from paraffin‐embedded tissues were dissected out for mutation analysis by conventional polymerase chain reaction ( PCR ) and Sanger sequencing. Tumours that appeared to have wild‐type KRAS by conventional PCR –Sanger sequencing were further analysed by full COLD (co‐amplification at lower denaturation temperature)‐ PCR and deep sequencing. Full COLD‐PCR was able to enrich the amplification of mutated alleles. Deep sequencing was performed with the Ion Torrent personal genome machine ( PGM ). By conventional PCR –Sanger sequencing, BRAF mutation was detected only in one patient and KRAS mutations were detected in ten patients. Full COLD‐PCR deep sequencing detected low‐abundance KRAS mutations in eight additional patients. Three of the five patients with both OSBT and LGSC samples available had the same KRAS mutations detected in both OSBT and LGSC samples. The remaining two patients had only KRAS mutations detected in their LGSC samples. For patients with either OSBT or LGSC samples available, KRAS mutations were detected in seven OSBT samples and six LGSC samples. Surprisingly, patients with the KRAS G12V mutation have shorter survival times. In summary, KRAS mutations are very common in recurrent LGSC , while BRAF mutations are rare. The findings indicate that recurrent LGSC can arise from proliferation of OSBT tumour cells with or without detectable KRAS mutations. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.