title: Mutational analysis of BRAF and KRAS in ovarian serous borderline (atypical proliferative) tumours and associated peritoneal implants.
abstract: There is debate as to whether peritoneal implants associated with serous borderline tumours/atypical proliferative serous tumours (SBT/APSTs) of the ovary are derived from the primary ovarian tumour or arise independently in the peritoneum. We analysed 57 SBT/APSTs from 45 patients with advanced-stage disease identified from a nation-wide tumour registry in Denmark. Mutational analysis for hotspots in KRAS and BRAF was successful in 55 APSTs and demonstrated KRAS mutations in 34 (61.8%) and BRAF mutations in eight (14.5%). Mutational analysis was successful in 56 peritoneal implants and revealed KRAS mutations in 34 (60.7%) and BRAF mutations in seven (12.5%). Mutational analysis could not be performed in two primary tumours and in nine implants, either because DNA amplification failed or because there was insufficient tissue for mutational analysis. For these specimens we performed VE1 immunohistochemistry, which was shown to be a specific and sensitive surrogate marker for a V600E BRAF mutation. VE1 staining was positive in one of two APSTs and seven of nine implants. Thus, among 63 implants for which mutation status was known (either by direct mutational analysis or by VE1 immunohistochemistry), 34 (53.9%) had KRAS mutations and 14 (22%) had BRAF mutations, of which identical KRAS mutations were found in 34 (91%) of 37 SBT/APST-implant pairs and identical BRAF mutations in 14 (100%) of 14 SBT/APST-implant pairs. Wild-type KRAS and BRAF (at the loci investigated) were found in 11 (100%) of 11 SBT/APST-implant pairs. Overall concordance of KRAS and BRAF mutations was 95% in 59 of 62 SBT/APST-implant (non-invasive and invasive) pairs (p < 0.00001). This study provides cogent evidence that the vast majority of peritoneal implants, non-invasive and invasive, harbour the identical KRAS or BRAF mutations that are present in the associated SBT/APST, supporting the view that peritoneal implants are derived from the primary ovarian tumour.
authors.affiliation: Departments of Pathology and Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Ardighieri
authors.forename: Felix
authors.initials: F
authors.lastname: Zeppernick
authors.forename: Charlotte G
authors.initials: CG
authors.lastname: Hannibal
authors.forename: Russell
authors.initials: R
authors.lastname: Vang
authors.forename: Leslie
authors.initials: L
authors.lastname: Cope
authors.forename: Jette
authors.initials: J
authors.lastname: Junge
authors.forename: Susanne K
authors.initials: SK
authors.lastname: Kjaer
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Kurman
authors.forename: Ie-Ming
authors.initials: IeM
authors.lastname: Shih
mesh_terms: D018284:Cystadenocarcinoma, Serous / Q000235:genetics* / Q000473:pathology; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000737:chemistry / Q000235:genetics; D003718:Denmark; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D061346:Laser Capture Microdissection; D009154:Mutation; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000473:pathology; D010534:Peritoneal Neoplasms / Q000235:genetics* / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics* / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras); D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D018631:ras Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D004273:DNA, Neoplasm; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins
keywords: ovarian low-grade serous carcinoma; ovarian neoplasms; serous borderline tumour