IDENTIFICATION OF EPSTEIN-BARR-VIRUS IN N ASOPHARYNGEAL CARCINOMAS INARGENTINA - ITS RELATION WITH P53 AND THE DETERMINATION OF PROLIFERATION INDEXES

Thirty-seven nasopharyngeal carcinomas were studied obtaining the tiss ue from nasopharyngeal biopsies that were formalin fixed and paraffin embedded. The patients were born in Argentina, 23 men and 14 women wit h a mean age of 50 years. Histologically the tumors were classified as queratinizing squamous cell carcinomas, 1 case (2%); non-queratinizin g squamous cell carcinomas, 15 cases (41%) and undifferentiated carcin omas, 21 cases (57%). The proliferating index (PI) was determined usin g monoclonal antibodies against PCNA and Ki-67 (MIB-1), resulting in 2 6% for PCNA and 17% for Ki-67 while no differences were found comparin g PI with histological type and cases with clinical stage III and IV. The PI was of 2% in the 3 cases with clinical stage II. Immunostains f or p53 were positive in 30 out of the 37 cases with no differences bet ween the histological types, exception made for the queratinizing carc inoma which was negative, With a cut off point of 7% in the 12 cases w ith follow up, two groups were found with a mean survival of 35 and 12 months, a finding that was not statistically significant. Epstein-Bar r virus was detected by PCR using the paraffin embedded material in 31 out of the 37 cases: 21 were undifferentiated carcinomas and 15 non-q ueratinizing squamous cell carcinomas; the queratinizing squamous cell carcinoma was negative. These results, published for the first time i n samples from Argentinian patients are similar to those found in area s of high and low incidence of nasopharyngeal carcinomas and can be of clinical use in determining the nasopharyngeal origin of a cervical m etastatic lymph node of an unknown primary.