Prostate cancer is the second most commonly diagnosed cancer in men in Poland after lung cancer and the third leading cause of cancer-related mortality after lung and colon cancer. The etiology of most cases of prostate cancer are not fully known, and therefore it is essential to search for the molecular basis of prostate cancer and markers for the early diagnosis of this type of cancer. Epigenetics deals with changes in gene expression that are not determined by changes in the DNA sequence. Epigenetic changes refer to changes in the structure of DNA, which are the result of DNA modification after replication and/or post-translational modification of proteins associated with DNA. In contrast to mutations, epigenetic changes are reversible and occur very rapidly. The major epigenetic mechanisms include DNA methylation, modification of histone proteins, chemical modification and chromatin remodeling changes in gene expression caused by microRNAs (miRNAs). Epigenetic changes play an important role in malignant transformation and can be specific to types of cancers including prostate cancer.

Genetic polymorphisms in DNA repair genes may induce individual variations in DNA repair capacity, which may in turn contribute to the risk of cancer developing. Homologous recombination repair (HRR) plays a critical role in maintaining chromosomal integrity and protecting against carcinogenic factors. The aim of the present study was to evaluate the relationship between prostate cancer risk and the presence of single nucleotide polymorphisms (SNPs) in the genes involved in HRR, that is, RAD51 (rs1801320 and rs1801321), RAD51B (rs10483813 and rs3784099), XRCC2 (rs3218536), and XRCC3 (rs861539). Polymorphisms were analyzed by PCR-RFLP and Real-Time PCR in 101 patients with prostate adenocarcinoma and 216 age- and sex-matched controls. A significant relationship was detected between the RAD51 gene rs1801320 polymorphism and increased prostate cancer risk. Our results indicate that the RAD51 gene rs1801320 polymorphism may contribute to prostate cancer susceptibility in Poland.

The term triple-negative breast cancer (TNBC) defines breast tumors that do not express estrogen receptors, progesterone receptor or epidermal growth factor receptor HER2 on immunohistochemical analysis. TNBC accounts for 12-17% of all types of breast cancer. Molecular profiling indicated that triple-negative breast cancer represents a heterogeneous subgroup of breast cancer. Triple-negative breast cancer shares histological and genetic abnormalities with basal-like subtype of breast cancer; however, this overlap is incomplete. Breast cancer found in BRCA1 mutation carriers is also frequently TNBC. Triple-negative breast cancer does not benefit from hormonal therapies or treatments targeted against HER2. The results of ongoing studies as well as the results of clinical trials suggest that poly(ADP-ribose) polymerase inhibitors, EGFR, Hedgehog, Notch, Wnt/β-catenin, VEGF signaling inhibitors, and mTOR, Src, and Bcr/Abl kinase inhibitors used alone or in combination with other anticancer drugs might be effective in triple-negative breast cancer treatment. In this review, current knowledge on molecular characteristics of triple-negative breast cancer and its subtypes' treatment options is presented.

Downregulation of betaglycan (β-glycan) [transforming growth factor β receptor type III (TGFβR3)], which belongs to co-receptors of the TGFβ pathway, occurs in a broad spectrum of primary human malignancies. However, in the case of endometrial cancer (EC), the mechanisms responsible for genetic alterations are still unknown. Therefore, we investigated allelic imbalance at the TGFBR3 locus (1p33‑p32) in the context of β-glycan mRNA and protein expression, as a possible genetic event determining β-glycan deregulation in EC patients. Study of β-glycan allelic imbalance in 48 primary human ECs was performed with the use of three different microsatellite markers, spanned within or in direct proximity to the TGFBR3 locus. Real‑time PCR and western blotting were used for β-glycan mRNA and protein quantification methods, respectively. Altogether, 25 of 39 (64%) informative cases and 25 of 48 (52%) of all specimens showed allelic imbalance in at least one microsatellite marker, concomitantly with decrease at both the β-glycan transcript and protein levels. Interestingly, 54% (15/28), 36% (8/22) and 35% (7/20) of informative ECs displayed allelic loss in D1S188, D1S435 and D1S1588 microsatellite markers, respectively. It is worth pointing out that 5 out of 39 (13%) informative cases showed loss of heterozygosity (LOH) at two microsatellite markers. Microsatellite instability (MSI) was found in two markers, but to a very strictly limited extent. None of the clinicoprognostic features was found to be of significance. Our results suggest that LOH in the TGFBR3 locus may be one of the mechanisms responsible for loss of β-glycan expression. No correlation of LOH at the TGFBR3 locus with clinicopathological parameters suggests that allelic imbalance may be an early genetic event during neoplastic transformation of human endometrium.

Recent studies suggest that genetic polymorphisms of the DNA repair genes have been implicated in breast cancer risk. BRCA1 and BRCA2, two breast cancer susceptibility genes, are essential to maintain chromosomal integrity. This is mediated via regulation of RAD51 during homologous recombination. Dinucleotide polymorphism repeats in the 15q14-21, 17q21 and 13q12-13 regions, where the RAD51, BRCA1 and BRCA2 genes are located, respectively, have been evaluated. The polymorphism was determined using the following microsatellite markers: D15S118, D15S214, D15S1006, D17S855, D17S1323, D13S260 and D13S290. Genotypes containing the (CA)(17) or (CA)(19) alleles in the RAD51 region were found to be associated with a decreased breast cancer risk. Genotype containing the (CA)(17) allele in the 13q12-13 region was found to be associated with an increased breast cancer risk. The results indicate that dinucleotide CA repeat polymorphism at RAD51 and BRCA2 gene regions might be associated with genetic susceptibility to breast cancer.