Ovarian high-grade serous carcinoma with transitional-like (SET) morphology: a homologous recombination-deficient tumor.

Thirteen years ago, we pointed out that ovarian transitional cell carcinomas (TCCs) and conventional high-grade serous carcinomas (HGSCs) had similar genetic alterations and clinical behavior. Consequently, ovarian TCC is now classified as a morphologic variant of HGSC. Defective homologous recombination, resulting from genetic or epigenetic inactivation of DNA damage repair genes, such as BRCA1/2, occurs in approximately 50% of the HGSCs. Although BRCA mutations have been associated with HGSCs with solid, pseudoendometrioid or transitional (SET) features, little is known about the role of non-BRCA homologous recombinationrepair (HRR) genes and the HRR status in these tumors. Using two commercially available assays (Myriad Genetics MyChoice CDx Plus test and SOPHiA Dx Homologous Recombination Deficiency Solution), we study mutations of BRCA1/2 and non-BRCA HRR genes (ATM, BARD1, BRIP1, CDK12, CHEK1/2, FANCL, PALB2, PPP2R2A, RAD51B, RAD51C, RAD51D, and RAD54L), and the HRR status in 19 HGSCs with SET features and 20 HGSCs with classic morphology. We also studied, as control cases, 5 endometrioid carcinomas, 1 clear cell carcinoma, 2 low-grade serous carcinomas, and 1 malignant Brenner tumor. Seven HGSCs with SET features (7/19; 37%) showed BRCA mutations (4 BRCA1, 2 BRCA2, and 1 BRCA1/2). Mutations in non-BRCA HRR genes were found in ATM (1/15; 7%), BARD1 (1/15; 7%), and BRIP1 (1/19; 5%). Most HGSCs with SET features (17/19; 90%) were considered to be homologous recombination-deficient tumors. Three HGSCs with classic morphology (3/20; 15%) showed BRCA2 mutations. Mutations in non-BRCA HRR genes were found in CDK12 (2/14; 14%), FANCL (1/14; 7%), RAD51B (1/14; 7%), and RAD54L (1/14; 7%). Eleven HGSCs with classical morphology (11/20; 55%) were considered to be homologous recombination deficient. In contrast, all ovarian carcinoma control cases (5 endometrioid carcinomas, 1 clear cell carcinoma, 2 low-grade serous carcinomas, and 1 malignant Brenner tumor) were homologous recombination proficient and did not have BRCA mutations. Our results show that the majority of HGSCs with SET features are homologous recombination-deficient tumors independently of the BRCA status and highlight the importance of the HRR tumor testing, especially in BRCA wild-type tumors. Recognition of transitional cell variant of HGSCs may help to identify patients most likely to benefit from PARP inhibitors.

D'Angelo E ，Espinosa I ，Felicioni L ，Buttitta F ，Prat J ... -  《-》

[Oncopathological aspects of BRCA1 and BRCA2 genes inactivation in tumors of ovary, fallopian tube and pelvic peritoneum].

Škapa P ，Dundr P 《-》

The clinical importance of BRCAness in a population-based cohort of Danish epithelial ovarian cancer.

Germline mutations in BRCA1/2 genes predict improved survival and sensitivity to treatment with poly(adenosine-diphosphate-ribose) polymerase inhibitors in epithelial ovarian carcinoma. The prognostic importance of other genetic alterations leading to homologous recombination deficiency, collectively BRCAness phenotype, is unresolved. The aim was to analyze the distribution of homologous recombination deficiency in epithelial ovarian carcinoma caused by mutations in a panel of homologous recombination genes (including BRCA1/2) or epigenetic alterations. A further aim was to investigate the prognostic importance of homologous recombination deficiency, the BRCAness phenotype. We assessed 380 patient specimens from a Danish population-based epithelial ovarian carcinoma cohort for germline and somatic mutations in 18 different homologous recombination genes, including BRCA1 and BRCA2, using next generation sequencing. Epigenetic alteration due to BRCA1 hypermethylation was assessed by pyrosequencing and BRCA1 protein expression was evaluated by immunohistochemistry. Seventeen percent of patients with epithelial ovarian carcinoma carried a germline (9.8%) and/or somatic (6.3%) mutation in 12 (BRCA1, BRCA2, CHEK2, ATM, RAD51D, EMSY, PALB2, BRIP1, ERCC1, RAD50, ATR, RAD51C) of 18 sequenced homologous recombination genes. The homologous recombination mutation rate was similar among the different histologic subtypes, however the type of mutation (BRCA1/2 and other homologous recombination mutations) differed, p=4×10-4. BRCA1 hypermethylation was present in 7.4% of patient specimens for a total BRCAness phenotype of 23.9%. The BRCAness phenotype was associated with improved overall survival in the high-grade serous carcinoma subgroup with a median overall survival of 4.4 years (95% CI 3.0 to 5.3) versus 2.2 years (95% CI 1.9 to 2.4) in BRCAness wildtype, p=0.0002. Multivariate analysis confirmed an independent prognostic value of the BRCAness phenotype among the high-grade serous carcinoma subgroup, hazard ratio 0.65 (95% CI 0.47 to 0.92), p=0.014. The BRCAness phenotype is present in almost one-fourth of epithelial ovarian carcinoma and holds important prognostic information. The implications of our findings in relation to poly(adenosine-diphosphate-ribose) polymerase inhibitor treatment call for further investigation.

Hjortkjær M ，Malik Aagaard Jørgensen M ，Waldstrøm M ，Ørnskov D ，Søgaard-Andersen E ，Jakobsen A ，Dahl-Steffensen K ... -  《-》

Evidence for a dualistic model of high-grade serous carcinoma: BRCA mutation status, histology, and tubal intraepithelial carcinoma.

Howitt BE ，Hanamornroongruang S ，Lin DI ，Conner JE ，Schulte S ，Horowitz N ，Crum CP ，Meserve EE ... -  《-》

Recurrent urothelial carcinoma-like FGFR3 genomic alterations in malignant Brenner tumors of the ovary.

Lin DI ，Killian JK ，Venstrom JM ，Ramkissoon SH ，Ross JS ，Elvin JA ... -  《-》