Collagen Type IV as Independent Prognostic Factor for Non-Hodgkin’s Lymphoma.

Many attempts have been made recently to improve the prognostic systems for non-Hodgkin’s lymphoma (NHL). There are no available data in the literature regarding the influence of intactness of the basement membrane of the blood vessels on the prognosis of NHL, when compared with the clinical characteristics of the disease. On the other hand, it is known that the integrity of the basement membrane is marker for the aggressiveness of the malignant disorders.

In order to analyze the association of the expression patterns of collagen type IV on the prognosis of the patients with NHL we have conducted a retrospective study.

We have evaluated 136 patients diagnosed and treated as NHL in the last ten years at the Clinic of Hematology, Medical Faculty -Skopje. All 136 patients with representative tumor tissues were diagnosed with NHL according to the REAL classification (71 patients were diagnosed as diffuse large cell lymphoma, 28 as follicular lymphoma, 24 as small lymphocytic lymphoma and 14 as marginal zone lymphoma). Median age of the patients was 49 years, with male: female ratio 1.5:1.0. The application of international prognostic index (IPI) identified four risk groups with predicted five-years survival rates of 87%, 82%, 18% and 0%, with statistical significance (p< 0.001).

Using immunoperoxidase staining we have analyzed the collagen type IV expressing patterns in our group of patients, and defined three tumor invasive grades: high tumor invasive grade as total lack of immunoreactivity for collagen type IV (68 patients), medium-presented as discontinuous expression (56 patients) and low-as a continuous linear expression (14 patients). The 5 year overall survival rate was significantly lower (p<0.01) in patients with high invasive grade than in patients with medium or low invasive grade (54% vs. 78% and 100%). Further, in multivariate analysis collagen type IV expression appeared as an independent survival-predicting factor together with the parameters of the IPI.

Our results indicated that the expression of a collagen type IV immunoreactivity could predict the outcome of patients with NHL. However, further studies are needed to define the role of collagen type IV in the future prognostic systems for NHL.