BackgroundPALB2 protein was recently identified as a partner of BRCA1 and BRCA2 which determines their proper function in DNA repair.MethodsInitially, the entire coding sequence of the PALB2 gene with exon/intron boundaries was evaluated by the PCR-SSCP and direct sequencing methods on 70 ovarian carcinomas. Sequence variants of interest were further studied on enlarged groups of ovarian carcinomas (total 339 non-consecutive ovarian carcinomas), blood samples from 334 consecutive sporadic and 648 consecutive familial breast cancer patients, and 1310 healthy controls from central Poland.ResultsTen types of sequence variants were detected, and among them four novel polymorphisms: c.2996+58T>C in intron 9; c.505C>A (p.L169I), c.618T>G (p.L206L), both in exon 4; and c.2135C>T (A712V) in exon 5 of the PALB2 gene. Another two polymorphisms, c.212-58A>C and c.2014G>C (E672Q) were always detected together, both in cancer (7.5% of patients) and control samples (4.9% of controls, p = 0.2). A novel germline truncating mutation, c.509_510delGA (p.R170fs) was found in exon 4: in 2 of 339 (0.6%) unrelated ovarian cancer patients, in 4 of 648 (0.6%) unrelated familial breast cancer patients, and in 1 of 1310 controls (0.08%, p = 0.1, p = 0.044, respectively). One ovarian cancer patient with the PALB2 mutation had also a germline nonsense mutation of the BRCA2 gene.ConclusionsThe c.509_510delGA is a novel PALB2 mutation that increases the risk of familial breast cancer. Occurrence of the same PALB2 alteration in seven unrelated women suggests that c.509_510delGA (p.R170fs) is a recurrent mutation for Polish population.

PI3K/AKT signalling pathway controls important cellular processes such as the cell proliferation and apoptosis. PIK3CA gene encoding a catalytic subunit of the PI3K is mutated and/or amplified in various neoplasms, including ovarian cancer. We aimed to evaluate PIK3CA alterations and their clinical importance in ovarian cancer patients. Molecular analysis was performed on 117 ovarian carcinomas with the use of qPCR, SSCP and sequencing. In a group of 98 patients with complete clinical data, 62 patients were treated with standard taxane-platinum regimens and 36 patients with platinum-cyclophosphamide regimens. A multivariate analysis was performed by the Cox's and logistic regression models. PIK3CA mutations occurred in 5/117 (4.3%) carcinomas, exclusively in the endometrioid and clear cell types (p = 0.0002); they were also associated with low FIGO stage (p = 0.0003), low tumor grade (p = 0.045) and early patient's age at diagnosis (p = 0.0005). The PIK3CA amplification (predominantly a low-level) was found in 28/117 (24%) ovarian carcinomas. It was more frequent in TP53 mutant tumors (p = 0.012) and tended to associate with high pAKT expression (p = 0.061). The PIK3CA amplification strongly diminished odds of complete remission (OR = 0.25, p = 0.033) and platinum sensitive response (PS, OR = 0.12, p = 0.004) in the taxane-platinum treated patients. The odds of PS were also much lower in all patients with the PIK3CA amplification evaluated together, regardless of the treatment applied (OR = 0.18, p = 0.001). Our results suggest that PIK3CA amplification may be a marker predicting ovarian cancer response to chemotherapy.