title: KRAS (but not BRAF) mutations in ovarian serous borderline tumour are associated with recurrent low-grade serous carcinoma.
abstract: BRAF 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.
authors.affiliation: Department of Gynecologic Oncology and Reproductive Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.
authors.forename: Yvonne T
authors.initials: YT
authors.lastname: Tsang
authors.forename: Michael T
authors.initials: MT
authors.lastname: Deavers
authors.forename: Charlotte C
authors.initials: CC
authors.lastname: Sun
authors.forename: Suet-Yan
authors.initials: SY
authors.lastname: Kwan
authors.forename: Eric
authors.initials: E
authors.lastname: Kuo
authors.forename: Anais
authors.initials: A
authors.lastname: Malpica
authors.forename: Samuel C
authors.initials: SC
authors.lastname: Mok
authors.forename: David M
authors.initials: DM
authors.lastname: Gershenson
authors.forename: Kwong-Kwok
authors.initials: KK
authors.lastname: Wong
mesh_terms: D000328:Adult; D000368:Aged; D001562:Benzimidazoles / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects; D018284:Cystadenocarcinoma, Serous / Q000235:genetics* / Q000473:pathology; D018293:Cystadenoma, Serous / Q000235:genetics* / Q000473:pathology; D004252:DNA Mutational Analysis / Q000379:methods; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods; D006801:Humans; D053208:Kaplan-Meier Estimate; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors; D008875:Middle Aged; D009154:Mutation; D060787:Neoplasm Grading; D009363:Neoplasm Proteins / Q000235:genetics; D009364:Neoplasm Recurrence, Local / Q000235:genetics* / Q000473:pathology; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000473:pathology; D011379:Prognosis; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D014407:Tumor Cells, Cultured; D055815:Young Adult; D018631:ras Proteins / Q000235:genetics*
chemical_list: C517975:AZD 6244; D001562:Benzimidazoles; D004273:DNA, Neoplasm; C117307:KRAS protein, human; D009363:Neoplasm Proteins; D047428:Protein Kinase Inhibitors; D011518:Proto-Oncogene Proteins; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D020930:MAP Kinase Kinase Kinases; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins
keywords: BRAF; COLD-PCR; KRAS; deep sequencing; mutation; ovarian low-grade serous carcinoma; serous borderline tumour