RESUMO
Thirty-seven nasopharyngeal carcinomas were studied obtaining the tissue from nasopharyngeal biopsies that were formalin fixed and paraffin embedded. The patients were born in Argentina, 23 men and 14 women with a mean age of 50 years. Histologically the tumors were classified as queratinizing squamous cell carcinomas, 1 case (2%); non-queratinizing squamous cell carcinomas, 15 cases (41%) and undifferentiated carcinomas, 21 cases (57%). The proliferating index (PI) was determined using monoclonal antibodies against PCNA and Ki-67 (MIB-1), resulting in 26% for PCNA and 17% for Ki-67 while no differences were found comparing 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 for p53 were positive in 30 out of the 37 cases with no differences between the histological types, exception made for the queratinizing carcinoma which was negative. With a cut off point of 7% in the 12 cases with follow up, two groups were found with a mean survival of 35 and 12 months, a finding that was not statistically significant. Epstein-Barr virus was detected by PCR using the paraffin embedded material in 31 out of the 37 cases: 21 were undifferentiated carcinomas and 15 non-queratinizing squamous cell carcinomas; the queratinizing squamous cell carcinoma was negative. These results, published for the first time in samples from Argentinian patients are similar to those found in areas of high and low incidence of nasopharyngeal carcinomas and can be of clinical use in determining the nasopharyngeal origin of a cervical metastatic lymph node of an unknown primary.
