Gastrointestinal stromal tumors - quantitative detection of the Ki-67, TPX2, TOP2A, and hTERT telomerase subunit mRNA levels to determine proliferation activity and a potential for aggressive biological behavior.

Gastrointestinal stromal tumors (GISTs) have an unpredictable biological potential ranging from benign to malignant. Molecular markers involved in the mechanisms of proliferation and cellular senescence may provide additional information about biological behavior of the tumor. The aim of the present study was to investigate Ki-67, TPX2, TOP2A and hTERT mRNA expression levels in specimens from patients with GISTs to define relationships between proliferation activity and biological potential and progression of the disease. We measured Ki-67, TPX2, TOP2A and hTERT mRNA levels using quantitative real-time reverse transcription PCR (RQ RT PCR). The highest Ki-67, TPX2, TOP2A and hTERT mRNA expression levels were found in the highly proliferative BLs (18 specimens), in comparison with GISTs (137 specimens) and LMSs (9 specimens). Patients with GISTs and adequate information about mitotic activity, tumor size and anatomical site (84 specimens) were divided into two groups - GISTs with benign (29 patients) and with malignant (55 patients) potential. We observed association between higher Ki-67, TPX2 and hTERT mRNA levels and the GISTs with malignant potential. Univariate analysis (57 patients with available follow-up information) of survival (Kaplan Meier curves method) revealed a correlation between higher levels of TPX2, Ki-67 and hTERT markers and shorter event-free survival (EFS) or poorer overall survival (OS). The results demonstrate the importance of quantitative assessment of the proliferation activity in GISTs. Proliferation markers of Ki-67, TPX2, TOP2A and hTERT are suitable markers for detection the proliferation activity and telomerase activity of these tumors. Furthermore, the assessment of TPX2, Ki-67 and hTERT expression levels is appropriate for determination of malignant potential of GISTs.

Quantitative molecular analysis in mantle cell lymphoma.

A molecular analysis has three major roles in modern oncopathology--as an aid in the differential diagnosis, in molecular monitoring of diseases, and in estimation of the potential prognosis. In this report we review the application of the molecular analysis in a group of patients with mantle cell lymphoma (MCL). We demonstrate that detection of the cyclin D1 mRNA level is a molecular marker in 98% of patients with MCL. Cyclin D1 quantitative monitoring is specific and sensitive for the differential diagnosis and for the molecular monitoring of the disease in the bone marrow. Moreover, the dynamics of cyclin D1 in bone marrow reflects the disease development and it predicts the clinical course. We employed the molecular analysis for a precise quantitative detection of proliferation markers, Ki-67, topoisomerase IIalpha, and TPX2, that are described as effective prognostic factors. Using the molecular approach it is possible to measure the proliferation rate in a reproducible, standard way which is an essential prerequisite for using the proliferation activity as a routine clinical tool. Comparing with immunophenotyping we may conclude that the quantitative PCR-based analysis is a useful, reliable, rapid, reproducible, sensitive and specific method broadening our diagnostic tools in hematopathology. In comparison to interphase FISH in paraffin sections quantitative PCR is less technically demanding and less time-consuming and furthermore it is more sensitive in detecting small changes in the mRNA level. Moreover, quantitative PCR is the only technology which provides precise and reproducible quantitative information about the expression level. Therefore it may be used to demonstrate the decrease or increase of a tumor-specific marker in bone marrow in comparison with a previously aspirated specimen. Thus, it has a powerful potential to monitor the course of the disease in correlation with clinical data.

[Molecular diagnosis of malignant B-cell lymphoma: detection of clonality and a brief review of problems with our results]. / Molekulární diagnostika maligních lymfomu rady B: detekce klonality a strucný prehled problematiky s vlastními výsledky.

BACKGROUND: Diagnostic approach to non-Hodgkin's lymphomas requires a combination of laboratory methods. Methods used in morphology constitute the basis of the diagnostics; in many instances it is necessary to combine them with methods of molecular genetics. The latter method plays a key role in the detection of B cell clonality using identification of the rearrangement of IGH and/or IGK genes and in detection of the chromosomal translocations specific for some lymphomas. METHODS AND RESULTS: Using PCR we investigated 113 patients with malignant B cell lymphomas of different types (follicular--FL, mantle cell--MCL, small cell--CLL/SLL, diffuse large cell--DLBCL). We established the IGH gene clonal rearrangement in 85% of the cases (96/113), and the clonal rearrangement of the IGK gene in 58.3% patients (42/72). Combination of both approaches (IGH and IGK) revealed a positive result in 90.3% (102/113). The highest yield was rendered in patients with CLL/SLL and with MCL (100%), and it was 86 and 87% in cases with FL and DLBCL. CONCLUSIONS: The detection of clonality in lymphomas helps to distinguish a malignant disease from polyclonal hyperplastic and lymphoproliferative disorders of B cells. The recognition of clonal rearrangements of the IGH and IGK genes serves for a long term monitoring of the disease activity in cases in which there are no other molecular markers available. The demonstration of lymphoma characteristic translocations is relatively specific and useful but at present its usefulness is reduced in cases with variable breakpoint regions.

Ethanol fixation of lymphoma samples as an alternative approach for preservation of the nucleic acids.

Molecular methods play an important role in diagnostic pathology of lymphomas. PCR based demonstration of clonality or detection of a specific chromosomal translocation may determine the exact classification of the lymphoma. Hence the final diagnosis may depend on the quality of preserved nucleic acids in the bioptic specimen. The integrity of DNA and RNA may be damaged by formalin fixation, which destroys the nucleic acids by fragmentation. Therefore, a portion of each lymphoma sample should be frozen. To substitute freezing techniques we utilized ethanol as a fixative, which preserves nucleic acids. We compared PCR and RT-PCR products from lymphoma samples, which were differently pre-treated by ethanol fixation, formalin fixation and freezing. The ethanol fixed samples retained a high quality of both DNA and RNA and provided reproducible PCR products similar to frozen samples and significantly better then those extracted from formalin fixed samples. We may recommend ethanol as a complementary fixative for all pathology laboratories where deep freezing in not routinely available.