Telomerase is perceived as an immortality enzyme that enables passing the Hayflick limit. Its main function is telomere restoration but only in a limited group of cells, including cancer cells. Since it is found in a vast majority of cancer cells, it became a natural target for cancer therapy. However, it has much more functions than just altering the metabolism of telomeres-it also reveals numerous so-called non-canonical functions. Thus, a question arises whether it is always beneficial to turn it off when planning a cancer strategy and considering potential side effects? The purpose of this review is to discuss some of the recent discoveries about telomere-independent functions of telomerase in the context of cancer therapy and potential side effects.

Expression of MIR125A is diminished in breast tumors, however the reason for the hsa-mir-125a decrease in the cancer is not known. HER2 is encoded by ERBB2, a target for hsa-miR-125a which interacts with the 3′UTR of ERBB2 mRNA. The present study reveals that a polymorphism (rs12976445) within the pri-miR-125a sequence correlates with the amount of mature hsa-miR-125a in breast tumor samples. miRNA, RNA and DNA were extracted from breast cancer samples obtained from 26 patients. Following immunohistological evaluation of the samples, the ERBB2, PGR and ESR1 mRNA profiles were also analyzed using real-time PCR. Genomic DNA was sequenced using MIR125A flanking primers. PCR products were analyzed using a BaeGI restriction enzyme specific to the rs12976445 variant. The rs12976445 variant (C/T and C/C) correlated with a lower level of hsa-miR-125a in comparison with the T/T variant. The expression of HER2 mRNA was increased in tumors with the rs12976445 variant (C/T and C/C) compared with T/T. We conclude that rs12976445 may be a potential prognostic marker of HER2 expression in breast cancer. Its predictive value on the efficacy of trastuzumab treatment in patients with HER2-positive breast cancer warrants further study.

Thus, no significant differences in the studied polymorphism frequencies were observed. It is then suggested that the studied polymorphisms, although probably good candidates in other tissue cancer types, might not be good predictive factors in breast cancer risk or development in Caucasians.

Abstract.Telomere shortening is associated with cancer development, primarily through the induction of genomic instability. The majority of studies have indicated that individuals with shorter blood telomeres may be at a higher risk of developing various types of cancer. There is increasing evidence that the study of the alterations in telomere length may improve cancer prognosis. The aim of the present study was to verify the use of telomere length parameters in the diagnostics of breast cancer stage. Telomere length was analyzed in the blood leukocytes of 52 patients with breast cancer relative to 47 control subjects using quantitative polymerase chain reaction. The effects of stage, grade, estrogen receptor, progesterone receptor and human epidermal growth factor 2 (HER2) status were assessed. The current study demonstrated that the average telomeric sequence length was significantly shorter in leukocytes from individuals diagnosed with a more severe stage of breast cancer (T2N1M0) than in leukocytes in the early stages of the disease (T1N0M0) (P=0.0207). Furthermore, the data indicated that telomeres in leukocytes derived from patients with HER2 + breast cancer were significantly longer compared with those with the HER2 -type (P=0.0347). These results suggest that the assessment of telomeres in blood leukocytes may, at least partially, correspond with breast cancer staging and HER2 receptor status.

Aim of the studyAssessment of the concentrations of the soluble forms of the cell adhesion molecules sVCAM-1 and sICAM-1 in serum of female breast cancer patients. These concentrations were assessed in relation to factors such as: age, clinical stage of disease, histological grade of malignancy, the status of the local axillary lymph nodes, and the size of the primary tumour.Material and methodsA total of 103 patients with primary breast cancer, aged 29 to 89 years, were investigated. The control group consisted of 40 healthy women. The concentration of sVCAM-1 and sICAM-1 was assessed using an enzyme-linked immunosorbent assay (ELISA).ResultsThe results of the study suggest that the level of sVCAM-1 and sICAM-1 in the serum of women with breast cancer was significantly higher than that seen in the serum of healthy women. A relationship between the level of adhesion molecules and the stage of clinical disease advancement was discovered. There was a correlation between the increasing concentrations of sVCAM-1 and sICAM-1 and with the aggressiveness of the disease. Significant differences were also found in the group of women with metastases to the axillary lymph nodes and women with no metastasis. Similar correlations were found between sVCAM-1 and sICAM-1 levels and the size of primary tumour.ConclusionsThe results obtained suggest that the assessment of the soluble forms of sVCAM-1 and sICAM-1 may be useful indicators in the assessment of the clinical advancement of breast cancer.