Daniel Tvrdík

Comparison of the IHC, FISH, SISH and qPCR methods for the molecular diagnosis of breast cancer.

Her2 proto-oncogene amplification and protein overexpression is observed in 20-40% of patients with breast cancer and plays a crucial role in invasive breast cancer and its treatment. In the present study, we investigated samples from 131 patients with invasive breast carcinoma. In all cases, the overexpression/amplification level of Her2 was determined using manual immunohistochemistry (IHC) and/or automatic IHC, fluorescence in situ hybridization (FISH), silver in situ hybridization (SISH) and quantitative polymerase chain reaction (qPCR). Using various methods, we demonstrated candidate methods for Her2 detection and their dependability. Our results demonstrate that these methods are highly comparable for the detection of Her2 overexpression/amplification. It was also revealed that qPCR is a valuable tool for the evaluation of Her2 gene overexpression/amplification. The results from pPCR analysis positively correlated with the results from IHC and FISH analysis. Moreover, in contrast to IHC or SISH/FISH, the results obtained by qPCR were not encumbered with any subjective error on the part of the evaluator.

Cyclin D-cdk6 complex is targeted by p21WAF in growth-arrested lymphoma cells

Normal human B lymphocytes are sensitive to the growth-inhibitory action of transforming growth factor beta1 (TGFbeta1) whereas malignant B lymphoma cells are mostly resistant to TGFbeta1 effects. We examined the phosphorylation status of retinoblastoma protein and the activity of G(1) cyclin-dependent kinases (cdk) in TGFbeta1-sensitive malignant follicular lymphoma cells during the TGFbeta1 treatment. The kinase activity of cdk2, cdk4, and cdk6 was significantly reduced and hypophosphorylation of pRb on serine 795 (S795) and threonine 373 (T373) was observed. We examined the composition of cdk complexes and the level of cdk inhibitors to explain the inhibitory action of TGFbeta1 toward cdk activity. Both cdk4 and cdk6 were notably dissociated from cyclin D cofactors, while cyclin E-cdk2 complexes remained coupled in TGFbeta1-treated cells. TGFbeta1-induced growth arrest was associated with notably increased binding of p21(WAF1) to cdk4 and cdk6. No induction of cdk-inhibitor molecules of INK family was observed in TGFbeta1-treated DoHH2 cells. As shown, TGFbeta1-induced growth arrest of malignant B cells was associated with the activation of CIP/KIP family members of cdk inhibitors.

Apoptosis – associated genes and their role in predicting responses to neoadjuvant breast cancer treatment

Summary Background Neoadjuvant chemotherapy is used in the treatment of breast carcinoma because it substantially reduces the size of the primary tumor and lymph node metastases. The present study investigated biomarkers that can predict a pathologic response to the therapy. Material/Methods The role of apoptosis in regression of the tumors after neoadjuvant chemotherapy was determined by TUNEL and anti-active caspase 3 assay. The transcriptional profile of 84 key apoptosis genes was evaluated in both pre-therapeutically obtained tumor tissue by core needle biopsy and in specimens removed by final surgery, using a pathway-specific real-time PCR assay. Obtained data were analyzed by hierarchical cluster analysis and correlation analysis. The immunohistochemical profile of each tumor was determined using the standard ABC method. Results On the basis of a hierarchical cluster analysis of 13 significantly changed genes, we divided patients into good and poor prognosis groups, which correlate well with progression-free survival. In the good prognosis group, we found a statistically significant down-regulation of the expression of MCL1 and IGF1R genes after neoadjuvant treatment. We also found a statistically significant overexpression of BCL2L10, BCL2AF1, CASP8, CASP10, CASP14, CIDEB, FADD, HRK, TNFRSF25, TNFSF8 and CD70 genes. In contrast, we found up-regulation of IGF1R after the treatment in the group with poor prognosis. Conclusions Gene expression profiling using real-time PCR assay is a valuable research tool for the investigation of molecular markers, which reflect tumor biology and treatment response.

Distribution of chondrocytes containing alpha-smooth muscle actin in human normal, osteoarthrotic, and transplanted articular cartilage

The aim of our study was to evaluate the occurrence of chondrocytes containing alpha-smooth muscle actin in human normal and diseased cartilage. Immunohistochemistry using monoclonal antibodies for alpha-smooth actin, muscle-specific actin, S-100 protein, CD 34, and desmin was performed on samples of human articular cartilage obtained at autopsy following sudden death, during total hip and knee replacement for osteoarthritis, or after femoral neck fracture in patients without symptoms of osteoarthritis. Moreover, the layers of residual cartilage from chondral posttraumatic defects obtained during preoperative arthroscopy and of newly formed cartilage after autologous-chondrocyte transplantation (Hyalograft C) obtained during second-look arthroscopy were also examined by immunohistochemistry and RT PCR. Our study showed that a significant percentage of articular chondrocytes express alpha-smooth muscle actin in healthy, diseased, and regenerated articular cartilage. Alpha-actin positive chondrocytes (18%) were observed predominantly in the upper zone of normal articular cartilage. By contrast, only approximately 10% of cartilage cells in the deep region stained for this contractile actin isoform. Actin-positive chondrocytes (myochondrocytes) are formed predominantly in response to injury to the osteoarthrotic cartilage, at sites of defective healing, and in newly formed cartilage after autologous chondrocyte transplantation. Fibrocartilage is present in some of these conditions, and it is known that this tissue contains chondrocytes with actin. The presence of myochondrocytes in the surface layer of normal articular cartilage indicates that this region probably plays an important role in maintaining cartilage integrity. Myochondrocytes may utilize the contractile actin isoform in manipulating the extracellular matrix of articular cartilage. It is also possible that actin-containing chondrocytes have a higher potential for regeneration in contrast to chondrocytes that do not contain this contractile material in their cytoplasm.