P53, C-MYC P62 AND PROLIFERATING CELL NUCLEAR ANTIGEN (PCNA) EXPRESSION IN NON-HODGKINS-LYMPHOMAS

Aims-To investigate the immunohistochemical expression of p53 protein in non-Hodgkin's lymphomas (NHL) and its relation to that of c-myc p62 oncoprotein and proliferating cell nuclear antigen (PCNA). Methods-Pa raffin wax embedded tissue from 90 non-Hodgkin's lymphomas (72 B cell and 18 T cell) was stained immunohistochemically for p53 protein, c-my c p62 oncoprotein, and PCNA using the monoclonal antibodies DO7, c-myc 1-9 E10, and PC-10, respectively. Results-Of the non-Hodgkin's lympho mas studied, 55 (61%) stained positively for p53 protein. The proporti on of positive cases increased from low grade through intermediate to high grade non-Hodgkin's lymphoma and was higher in tumours of T cell origin. The percentage of positive cells (labelling index or LI) was s ignificantly lower in low grade non-Hodgkin's lymphoma, but no differe nce was established between intermediate and high grade non-Hodgkin's lymphoma. In a large proportion of low grade non-Hodgkin's lymphoma th e LI was below 1%. c-myc p62 immunereactivity was identified in all ca ses. A significant positive correlation was established between p53 LI and c-myc p62 LI (r(s) = 0.453) as well as between p53 LI and PCNA LI (r(s) = 0.338). Conclusions-p53 immunoreactivity was present in about half the cases of non-Hodgkin's lymphoma and was related to the grade of malignancy and possibly to the B or T cell origin of the tumour. I t was also associated with the proliferation state as expressed by PCN A LI and c-myc p62 expression, indicating that the expression of these three cell cycle-related genes might be interrelated.