Comprehensive Analysis of PTEN in Primary Cutaneous Melanoma.

Phosphatase and tensin homologue (PTEN) is a tumour suppressor gene implicated in tumorigenesis of melanoma, with distinct cytoplasmic and nuclear functions. Cytoplasmic PTEN negatively regulates the PI3K/AKT/mTOR signalling pathway, while nuclear PTEN works as a tumour suppressor. Clinical data suggest that the loss of PTEN function in melanoma is associated with aggressive tumour behaviour. We performed a comprehensive analysis of PTEN in 112 primary cutaneous melanomas including immunohistochemical (IHC), fluorescent in situ hybridization (FISH), next-generation sequencing (NGS), and epigenetic analysis. The goal of our study was to: (a) correlate PTEN expression with selected clinico-pathological variables, and assess its prognostic significance; (b) correlate molecular aberrations with PTEN expression to consider the utility of immunohistochemical analysis of PTEN protein expression for screening PTEN genetic alterations; (c) review the literature and evaluate the PTEN expression level in melanoma with respect to possible therapeutic targeting. Our results showed that PTEN molecular alterations were present in 4/20 (20 %) cases with a loss of expression, 3/11 (27 %) cases with clonal-like expression, and 1/81 (1 %) cases with positive PTEN expression. No PTEN promoter methylation was found in any of the cases. Even though the value of our observation is limited by the low number of cases fully evaluated by IHC (112 cases), FISH (19 cases) and NGS (30 cases), our data suggest that IHC is not an appropriate method for the screening of PTEN genetic alterations. Our survival analysis suggests that patients with positive cytoplasmic PTEN expression show better disease-free survival (P < 0.05).

The Role of HNF1B in Tumorigenesis of Solid Tumours: a Review of Current Knowledge.

Hepatocyte nuclear factor 1-ß is a transcription factor which plays a crucial role during ontogenesis in the differentiation of visceral endoderm from primitive endoderm, and is especially important for the normal development of the kidney, urogenital tract, gastrointestinal tract, liver, and pancreas. Despite the growing knowledge about the potential involvement of hepatocyte nuclear factor 1-ß in the process of carcinogenesis, the exact underlying mechanism that would explain its rather varied effects in different tumours has not been sufficiently investigated. Most of the data regarding the significance of hepatocyte nuclear factor 1-ß arise from genome- wide association studies and is concerned with the influence of single-nucleotide polymorphisms of hepatocyte nuclear factor 1-ß on either the increased or decreased susceptibility to certain types of cancer. However, the influence of both the germinal and somatic mutations of this gene on the process of carcinogenesis is still poorly understood. According to current data, in some tumours hepatocyte nuclear factor 1-ß acts as a protooncogene, while in others as a tumour suppressor gene, although the reasons for this are not clear. The exact incidence of hepatocyte nuclear factor 1-ß mutations and the spectrum of tumours in which they may play a role in the process of carcinogenesis remain unknown. From the practical point of view, immunohistochemical expression of hepatocyte nuclear factor 1-ß can be used in differential diagnostics of certain tumours, especially clear cell carcinoma. In our article we review the current knowledge regarding the significance of hepatocyte nuclear factor 1-ß in carcinogenesis.

Assay of total glutathione and glutathione disulphide in seminal plasma of male partners of couples presenting for a fertility evaluation.

A method is described here for the determination of total glutathione (TGSH) and glutathione disulphide (GSSG) in the seminal plasma of the male partners of couples requesting a fertility evaluation. A suitable sample preparation procedure prior to high-performance liquid chromatography analysis is discussed. After adequate sample preparation, the samples were derivatised with ortho-phthaldialdehyde to form a stable, highly fluorescent tricyclic derivative. Reversed-phase column chromatography was used for the separation, and the effluent was monitored with a fluorescence detector at an excitation wavelength of 350 nm and an emission wavelength of 420 nm. The analytical performance of this method was satisfactory. The intra-assay and inter-assay coefficients of variation were below 10%. The recoveries were as follows: 94.1% (CV 2.3%) for TGSH and 93.2% (CV 4.0%) for GSSG. No significant differences were found in either TGSH or GSSG concentration between the smokers and nonsmokers (2.07 ± 1.28 µm versus 1.56 ± 1.20 µm, P = 0.431 and 95 ± 56 nm versus 112 ± 138 nm, P = 0.825).