[In situ detection of EBV DNA in various types of carcinomas derived from the nasopharynx and neighboring regions].

A sensitive and reliable technique for in situ hybridization of DNA-DNA with biotin labelled probe on routine paraffin sections was developed. Using BamH I-W fragment of EBV as probe, a variety of biopsies from nasopharynx and its neighboring regions were examined for EBV distribution. It was discovered that the existence of EBV was related to the histological type and degree of differentiation of carcinomas, but not limited to the nasopharynx region. The EBV DNA positive ratios in (1) poorly, (2) moderately and (3) well differentiated nasopharyngeal squamous cell carcinomas, (4) poorly differentiated nasopharyngeal adenocarcinoma, (5) poorly differentiated squamous cell carcinomas derived from palate and (6) tonsil were 39/41, 1/7, 0/3, 2/8, 3/4 and 2/9 respectively. No EBV DNA was detected in other moderately and well differentiated squamous cell carcinomas or benign tumors of the head and neck. EBV DNA was detected in nearly all malignant cell nuclei of positive sections, whereas all morphologically normal and hyperplastic epithelial cells, stroma cells, infiltrating lymphocytes and epithelium in chronic nasopharyngitis were negative.