Immunophenotyping, MIB-1, p53 and mast cell tryptase in large cell non-Hodgkin's lymphoma

ABSTRACT

The aim of the present study was to explore by immunohistochemical methods, on lymph node and infiltrated bone marrow bioposies. the potential value of MIB-l proliferation rate. p53 overexpression and Mast cell tryptase [MCT] as possible prognostic fators for large cell lymphomas on 69 adult patients for whom paraffin blocks, clinical data and survival information were available. In the reviewed series, large cell lymphoma included 84.1% large B-cell lymphoma. 11.6% peripheral T-cell lymphoma and 4.3% anaplastic large cell lymphoma. MIB-1 labeling was quantitated by image analysis and cases were classified as either of low or high proliferation rate taking MIB-l count of 50% as a cutoff value. For p53, nuclear immunoreactivity equal to or more than 20% were considered overexpression or positive. As for MCT, presence of> 5 mast cells/hpf was recorded as high count while counts <5 mast cells/hpf were considered low counts. In the L.N. biopsies examined the mean MIB-l labeling rate was 48.5%. p53 positive tumors contributed 33.3% of cases while high MCT counts were detected in 43.5% of cases. High MIB-l rate, p53 positivity and MCT counts showed a statistically significant relation to high lPl and were associated ".ith poor response to therapy and unfavorable 2-year overall survival and hence were considered risk factors. Additionally, high MCT count was found to show a strong relation with T-cell phenotype and extranodal forms. Bone marrow biopsies were examined to detect infiltrated cases. B.M. infiltration was detected in 15 cases whose levels of MIB-l and p53were in accordance to the corresponding L.N. values.MCT counts in B.M. biopsies were within the high count group but were lower than corresponding L.N. values and were strongly related to T-cell phenotype. It is concluded that MIB- 1. p53 and MCT are valuable prognostic factors which could serve as a guideline for treatment by identifying unfavorable cases for more intensive therapy