Clinical importance of FANCD2, BRIP1, BRCA1, BRCA2 and FANCF expression in ovarian carcinomas

Abstract

Objective: DNA repair pathways are potential targets of molecular therapy in cancer patients. The FANCD2, BRIP1, BRCA1/2, and FANCF genes are involved in homologous recombination DNA repair, which implicates their possible role in cell response to DNA-damaging agents. We evaluated a clinical significance of pre-treatment expression of these genes at mRNA level in 99 primary, advanced-stage ovarian carcinomas from patients, who later received taxane-platinum (TP) or platinum-cyclophosphamide (PC) treatment.

Methods: Gene expression was determined with the use of Real-Time PCR. The BRCA2 and BRIP1 gene sequence was investigated with the use of SSCP, dHPLC, and PCR-sequencing.

Results: Increased FANCD2 expression occurred to be a negative prognostic factor for all patients (PC+TP:HR 3.85, p = 0.0003 for the risk of recurrence; HR 1.96, p = 0.02 for the risk of death), and this association was even stronger in the TP-treated group (HR 6.7, p = 0.0002 and HR 2.33, p = 0.01, respectively). Elevated BRIP1 expression was the only unfavorable molecular factor in the PC-treated patients (HR 8.37, p = 0.02 for the risk of recurrence). Additionally, an increased FANCD2 and BRCA1/2 expression levels were associated with poor ovarian cancer outcome in either TP53-positive or -negative subgroups of the TP-treated patients, however these groups were small. Sequence analysis identified one protein truncating variant (1/99) in BRCA2 and no mutations (0/56) in BRIP1.

Conclusions: Our study shows for the first time that FANCD2 overexpression is a strong negative prognostic factor in ovarian cancer, particularly in patients treated with TP regimen. Moreover, increased mRNA level of the BRIP1 is a negative prognostic factor in the PC-treated patients. Next, changes in the BRCA2 and BRIP1 genes are rare and together with other analyzed FA genes considered as homologous recombination deficiency may not affect the expression level of analyzed genes.

Keywords: BRCA1; BRCA2; BRIP1; DNA repair; FANCD2; FANCF; FANCJ; TP53; gene expression; ovarian cancer.

Figure 1.

Disease-free survival (DFS) according to the FANCD2 gene expression at the mRNA level in the (a, b) combined TP- and PC-treated groups of patients; (c, d) TP-treated group of patients (e, f) group of TP-treated patients with TP53-positive carcinomas; (a, c, e) univariate analysis of a continuous variable; (b, d, f) analysis of Kaplan–Meier curves, cut-off point at the median value of 0.4.

Figure 2.

Overall survival (OS) according to the FANCD2 gene expression at the mRNA level in the (a, b) combined TP- and PC-treated groups of patients; (c, d) TP-treated group of patients; (e, f) group of TP-treated patients with TP53-negative carcinomas. (a, c, e) univariate analysis of a continuous variable; (b, d, f) analysis of Kaplan–Meier curves, cut-off point at the median value of 0.4.

Figure 3.

Association of analyzed FA genes median expression level and a mutation status of selected FA genes in ovarian cancer tumors: (a) combined TP- and PC-treated groups of patients – no significant relationship; (b) group of TP-treated patients with TP53-negative carcinomas – significant difference in median FANCD2 expression level.