The impact of oophorectomy on survival after breast cancer in BRCA1-positive breast cancer patients.

The aim of the study is to identify treatments which predict survival for women with a BRCA1 mutation, including oophorectomy and chemotherapy. 476 women with stage I to stage III breast cancer who carried a BRCA1 mutation were followed from diagnosis until April 2015. Information on treatment was obtained from chart review and patient questionnaires. Dates of death were obtained from the Poland vital statistics registry. Survival curves were compared for different subgroups according to treatment received. Predictors of overall survival were determined using the Cox proportional hazards model. The ten-year overall survival was 78.3 % (95 % CI 74.2-82.6 %) and the ten-year breast cancer-specific survival was 84.2 % (95 % CI 80.5-88.0 %). Sixty-two patients died of breast cancer, 14 patients died of ovarian cancer, and 2 patients died of peritoneal cancer. Oophorectomy was associated with a significant reduction in all-cause mortality in the entire cohort (adjusted HR = 0.41; 95 % CI 0.24-0.69; p = 0.0008) and in breast cancer-specific mortality among ER-negative breast cancer patients (HR = 0.44; 95 % CI 0.22-0.89; p = 0.02). Among women with breast cancer and a BRCA1 mutation, survival is greatly improved by oophorectomy due to the prevention of deaths from both breast and ovarian cancer.

Survival from breast cancer in patients with CHEK2 mutations.

The purpose of this study is to estimate 10-year survival rates for patients with early onset breast cancer, with and without a CHEK2 mutation and to identify prognostic factors among CHEK2-positive breast cancer patients. 3,592 women with stage I to stage III breast cancer, diagnosed at or below age 50, were tested for four founder mutations in the CHEK2 gene. Information on tumor characteristics and on treatments received was retrieved from medical records. Dates of death were obtained from the Poland Vital Statistics Registry. Survival curves were generated for the mutation-positive and -negative sub-cohorts. Predictors of survival were determined among CHEK2 carriers using the Cox proportional hazards model. 3,592 patients were eligible for the study, of whom 140 (3.9 %) carried a CHEK2-truncating mutation and 347 (9.7 %) carried a missense mutation. The mean follow-up was 8.9 years. The 10-year survival for all CHEK2 mutation carriers was 78.8 % (95 % CI 74.6-83.2 %) and for non-carriers was 80.1 % (95 % CI 78.5-81.8 %). Among women with a CHEK2-positive breast cancer, the adjusted hazard ratio associated with ER-positive status was 0.88 (95 % CI 0.48-1.62). Among women with an ER-positive breast cancer, the adjusted hazard ratio associated with a CHEK2 mutation was 1.31 (95 % CI 0.97-1.77). The survival of women with breast cancer and a CHEK2 mutation is similar to that of patients without a CHEK2 mutation.

Clinical characteristics of breast cancer in patients with an NBS1 mutation.

To identify characteristic features of breast cancers associated with an NBS1 mutation. To estimate and to compare 10-year survival rates for patients with early-onset breast cancer, with and without an NBS1 mutation. 4,566 women with stage I to stage III breast cancer, diagnosed at or below age 50, were tested for a founder mutation in the NBS1 gene. Information on tumor characteristics and on treatments received was retrieved from medical records. Dates of death were obtained from the Poland vital statistics registry. Survival curves for the mutation-positive and negative sub-cohorts were generated and were compared and the effect of an NBS1 mutation on survival was determined using the Cox proportional hazards model. 4566 patients were enrolled in the study, of whom 53 (1.2 %) carried a NBS1 mutation. Mutation carriers were similar to non-carriers in terms of tumor receptor status, grade, and lymph node status. The 10-year survival for NBS1 mutation carriers was 81.2 % (95 % CI 70.1-94.1 %) and for non-carriers was 79.4 % (95 % CI 78.0-80.9 %). The presence of an NBS1 mutation is not associated with prognosis (HR = 1.21; 95 % 0.67-2.19). The survival of women with breast cancer and a NBS1 mutation is similar to that of patients without a NBS1 mutation.

Germline MSH2 and MLH1 mutational spectrum including large rearrangements in HNPCC families from Poland (update study).

Germline mutations in the DNA mismatch repair genes MSH2 and MLH1 account for a significant proportion of hereditary non-polyposis colorectal cancer (HNPCC) families. One approach by which development of an efficient DNA-testing procedure can be implemented is to describe the nature and frequency of common mutations in particular ethnic groups. Two hundred and twenty-six patients from families matching the Amsterdam II diagnostic criteria or suspected HNPCC criteria were screened for MSH2 and MLH1 germline mutations. Fifty different pathogenic mutations were found, 25 in MSH2 and 25 in MLH1. Twenty-four of these had not previously been described in other populations. Among our 78 families with MSH2 or MLH1 mutations, 54 (69.2%) were affected by recurrent mutations including 38 found at least twice in our own series. Two of the most frequent alterations were a substitution of A to T at the splice donor site of intron 5 of MSH2 and a missense change (A681T) of MLH1 found in 10 and eight families, respectively. Among large deletions detected by the multiplex ligation-dependent probe amplification assay, exon 9 deletions in the MSH2 gene were found in two families. Our results indicate that a screening protocol specific for the Polish population that is limited to the detection of all reported mutations will result in the identification of the majority of changes present in MLH1 and MSH2 genes in Polish HNPCC kindreds.

Breast cancer predisposing alleles in Poland.

Mutant alleles of several genes in the DNA repair pathway have been found to predispose women to breast cancer. From a public health perspective, the importance of a given allele in a population is determined by the frequency of the allele and by the relative risk of breast cancer that it confers. In Poland founder alleles of the BRCA1, CHEK2 and NBS1 genes have been associated with an increased risk of breast cancer, but the relative contribution of each of these alleles to the overall breast cancer burden has not yet been determined. We screened 2012 unselected cases of breast cancer and 4000 population controls for 7 different mutations in these genes. Overall, a mutation was found in 12% of the cases and in 6% of the controls. Mutations in BRCA1 and CHEK2 contributed in approximately equal measure to the burden of breast cancer in Poland. A BRCA1 mutation was present in 3% of the cases. The missense BRCA1 mutation C61G was associated with a higher odds ratio for breast cancer (OR=15) than were either of the truncating BRCA1 mutations 4153delA (OR=2.0) and 5382insC (OR=6.2). In contrast, a higher odds ratio was seen for truncating CHEK2 mutations (OR=2.1) than for the missense mutation I157T (OR=1.4). This study suggests that cancer risks may be specific for particular alleles of a susceptibility gene and that these different risks should be taken into account by genetic counselors.

Frequency of three BRCA1 gene founder mutations in breast/ovarian cancer families from the Pomerania-Kujawy region of Poland.

A group of 63 families from the Pomerania-Kujawy region were analyzed for three BRCA1 gene Polish founder mutations, 5382insC, 300T>G, and 4153delA, because of breast (BrCa) and/or ovarian cancer (OvCa) history. The analysis was carried out by multiplex polymerase chain reaction method. BRCA1 mutation was revealed in nine (14%) families: in three (33%) of hereditary BrCa and OvCa families, in three (8%) of hereditary BrCa families, and in three (21%) of hereditary OvCa families. According to risk criteria, it was revealed in 45% of high-risk families with more than three cancers, 13% of moderate-risk families with two cancers, and 8% of families with sporadic OvCa. In six families, the mutation was found in a proband with BrCa or OvCa and in three families, the mutation was found in a healthy proband, first-degree relative of a patient deceased of BrCa or OvCa. 5382insC frameshift mutation accounted for 67% and 300T>G missense mutation for 33% of all identified familial mutations. 4153delA frameshift mutation was not found in analyzed sample of families. 5382insC mutation was found in 9% and 300T>G in 5% of all investigated families, and in 27 and 18%, respectively, of high-risk families. This underlines the importance of applying strict inclusion criteria to analyze mutation frequency in hereditary BrCa/OvCa families.