As regards their morphology and biology, tumours consist of heterogeneous cell populations. The cancer stem cell (CSC) hypothesis assumes that a tumour is hierarchically organized and not all of the cells are equally capable of generating descendants, similarly to normal tissue. The only cells being able to self-renew and produce a heterogeneous tumour cell population are cancer stem cells. CSCs probably derive from normal stem cells, although progenitor cells may be taken into consideration as the source of cancer stem cells. CSCs reside in the niche defined as the microenvironment formed by stromal cells, vasculature and extracellular matrix. The CSC assays include FACS sorting, xenotransplantation to immunodeficient mice (SCID), incubation with Hoechst 33342 dye, cell culture in non-adherent conditions, cell culture with bromodeoxyuridine. CSCs have certain properties that make them resistant to anticancer therapy, which suggests they may be the target for potential therapeutic strategies.

Uveal melanoma is the most prevalent primary intraocular cancer in adults. Although it accounts for only 5% of all melanomas, it is responsible for 13% of deaths due to this type of cancer. A wide variety of therapeutic options of primary tumor is available and progress in its management is noticeable. The fact still remains, however, that almost half of patients develop metastases which may be due to practically undetectable cancer spread present as early as at diagnosis of the primary focus. Metastatic disease is uniformly fatal despite systemic therapy. Prediction of metastasis is crucial for prognosis. It also allows targeting of emerging new therapeutic methods to the appropriate group of patients. The Authors reviewed literature concerning epidemiology and etiopathogenesis of uveal melanoma, and its clinical, histopathological and cytogenetic prognosticators.

Estrogen as a potential factor of ovarian carcinogenesis, acts via two nuclear receptors, estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), but the cellular signal pathways involved are not completely clear so far. In this study we have described the expression of ERα, detected by immunocytochemistry in 11 ovarian carcinoma cell lines and by immunohistochemistry in 43 Federation Internationale des Gyneacologistes et Obstetristes stage III ovarian carcinoma specimens prepared before and after treatment with cisplatin-based schemes. For cisplatin resistance is a major obstacle in the treatment of ovarian carcinoma, analysis of cisplatin sensitivity in 11 ovarian carcinoma cell line was also performed. The strong nuclear ERα expression was only shown in the single A2780P cell line. Expression of ERα in tissue specimens did not reveal any correlations between histopathological parameters (histologic type and grading). We demonstrated a significant association with ERα expression in specimens from primary laparotomies (PL) and cause–specific survival. In the cases terminated by death of the patient, overall immunoreactivity score of ERα expression at PL was significantly lower than in surviving patients. In addition, Kaplan-Meier analysis revealed significantly shorter overall survival time and progression-free time in cases with lower immunoreactivity score of ERα expression at PL. Our findings support the hypothesis that aberrant hormone activity, by way of altered receptor expression, might be an important factor in the malignant transformation of ovarian cancer.

Abstract. PARP-1 plays an important role in DNA damage repair and maintaining genome integrity by repairing DNA single-strand breaks (SSBs) by base excision repair (BER). The aim of the present study was to examine the expression of PARP-1 in breast cancer (BC) patients and to assess the relationship between the subcellular localization of this protein and clinicopathological characteristics. The reactivity of PARP-1 was analyzed by immunohistochemistry in a homogeneous group of 83 stage II ductal BC patients with a 15-year follow-up. Immunostaining of PARP-1 was also evaluated in 4 human BC cell lines and resistance prediction profile for 11 anticancer agents was performed using 3 models of drug-resistant cell lines. Nuclear-cytoplasmic expression (NCE) was associated with shorter overall survival, which was not statistically significant during the 10-year follow-up but became statistically significant after 10 years of observation, during the 15-year follow-up (P=0.015). Analysis performed in subgroups of patients with (N+) and without (N-) nodal metastases showed that NCE was associated with poor clinical outcome in N-patients (P=0.017). Multivariate analysis confirmed a significant impact of NCE on unfavorable prognosis in N-early BC. The presence of PARP-1 NCE may be a new potential unfavorable prognostic factor in lymph node-negative early BC.

Abstract. Cutaneous melanoma is an aggressive cancer and its onset and growth are associated, through direct and indirect interactions, with the cancer microenvironment. The microenvironment comprises a dynamic complex of numerous types of cells (due to histogenesis) that constantly interact with each other through multiple cytokines and signaling proteins. Macrophages are one of the most thoroughly studied pleiotropic cells of the immune system. One of their major cytophysiological functions is their involvement in phagocytosis. Previous studies examining the microenvironment of melanomas and tumor-associated macrophages have revealed that they are involved in all stages of melanomagenesis. In the case of cancer initiation, they form an inflammatory microenvironment and then suppress the anticancer activity of the immune system, stimulate angiogenesis, enhance migration and invasion of the cancer cells, and ultimately contribute to the metastatic process. The present review provides a detailed overview on the function of macrophages in the melanoma microenvironment. IntroductionMelanomas are a rare but aggressive cutaneous type of cancer in humans (1). At the dissemination stage in a majority of cases, the disease is resistant to treatment with cytostatics and radiotherapy (1). Therefore, the identification of novel molecular mechanisms involved in the melanomagenesis process and tumor progression have enabled the production of targeted therapies that yield notable effects (1). The basis for melanomagenesis is the accumulation of genetic disorders in the melanocyte (the most frequent ones include the following mutations: B-Raf proto-oncogene, serine/threonine kinase, N-Ras proto-oncogene, GTPase and phosphatase and tensin homolog) (1). However, only the interaction between microenvironment elements and genetic changes in the melanocyte result in the ultimate transformation of a dysplastic melanocyte into a melanoma cell, and at further stages result in the local invasion and dissemination of the primary lesion (1). It is the microenvironment that is one of the key elements of cancer formation and is being studied at present.A melanoma microenvironment is a markedly heterogenic population of cells that involves fibroblasts, macrophages, lymphocytes, other immune system cells, adipocytes and cells that form the structural elements of cutaneous blood vessels sunk in the extracellular matrix (2). The aforementioned complex network of cellular associations are constantly interacting through direct contact and active protein substances including secretory proteins (e.g., metalloproteinases or

PurposeThe aim of this study was to examine the expression of ERM (ezrin, moesin) and Rho (RhoA, RhoB and Cdc42) proteins in breast cancer (BC) patients and to investigate the relationship between the sub-cellular localisation of these proteins and clinicopathological characteristics and patient survival.MethodsThe expression and specific sub-cellular distribution of the ERM/Rho proteins was analysed by immunohistochemistry in a homogeneous group of 85 stage II ductal BC patients with a follow-up of 15 years.ResultsEnhanced immunoreactivity of all analysed proteins was found to be associated with the presence of lymph node metastases (ezrin, P = 0.047, moesin, P = 0.038, RhoA, P = 0.024, RhoB, P = 0.004 and Cdc42, P = 0.047). Nuclear localisation of ezrin was found to correlate with the presence of lymph nodes metastases (P = 0.004) and with histological de-differentiation (P = 0.015). In contrast, we found that the nuclear topography of RhoA and Cdc42, and the perinuclear localisation of RhoB, were strongly associated with a lack of nodal metastases (P = 0.008, P = 0.048, P = 0.001, respectively), whereas a decreased reactivity of RhoA in the stromal compartment of BC tumours was associated with the presence of lymph node metastases (P = 0.011). No relationship was observed between ERM/Rho protein expression and oestrogen receptor (ER), progesterone receptor (PgR) or HER-2 reactivity in the BC cells. Also, ERM/Rho protein expression did not predict patient survival, but RhoB over-expression in the stromal compartment of the tumours was found to be associated with a better prognosis (P = 0.0106).ConclusionsThe ERM/Rho immunoprofile and the assessment of its specific sub-cellular localisation may be instrumental for the prediction of lymph node metastases in ductal BC patients.

The results indicate that COX-2 may be involved in the pathogenesis of the photoaging process. Inhibition of expression or activity of the enzyme may find application in photoaging treatment and/or prophylaxis.

Polo-like kinase 1 (PLK1) is a serine-threonine kinase that plays a crucial role in the regulation of cell division. In addition, it acts as a modulator of the DNA damage response and as a novel factor in the maintenance of genome stability during DNA replication. The present study aimed to reveal the associations between PLK1 expression and clinicopathological features of patients with breast cancer (BC), particularly patient survival at 5-, 10- and 15-year follow-up. PLK1 expression was evaluated immunohistochemically in routine diagnostic tissue specimens from 83 patients treated radically for stage II BC. Kaplan-Meier analysis revealed a correlation between PLK1 overexpression and long-term survival. High PLK1 immunoreactivity was associated with shorter cancer-specific overall survival (CSOS) and disease-free survival (P=0.00001 and 0.00013, respectively). Multivariate analysis confirmed the negative prognostic significance of PLK1 overexpression for CSOS in all 83 patients (P=0.00030). Furthermore, analogous correlations were observed in both subgroups with and without nodal metastases (P=0.01400 and 0.01200, respectively). The present results indicate that PLK1 expression has a prognostic role in early BC. Immunohistochemical assessment of PLK1 reactivity may potentially become a qualifier for inclusion of PLK1 inhibitor therapy.