Summary.-Biopsy specimens from nasopharyngeal carcinomas (NPC) or salivarygland carcinomas (SGC) in Greenland Eskimoes were examined for the presence of Epstein-Barr virus (EBV) DNA and sera from the patients were tested for EBVspecific antibody titres. Six out of 7 NPCs and one from an undifferentiated SGC were positive for EBV DNA. The EBV-specific antibody spectra and titres of the patients with NPC or undifferentiated SGC conformed to the results of earlier studies in other high-incidence areas.
Most nasopharyngeal carcinomas (NPCs) are of the nonkeratinizing or undifferentiated types, which are consistently associated with Epstein-Barr virus (EBV). The smaller group of highly differentiated, keratinizing NPCs seems to be only infrequently associated with EBV. In order to examine whether these rare tumors were related to another oncogenic virus, the authors used the polymerase chain reaction to examine paraffin-embedded sections of 15 keratinizing NPCs for human papillomavirus (HPV) types 6, 11, 16, and 18 genomic sequences. HPV DNA was found in 4 tumors (1 HPV-11-positive, and 3 HPV-16-positive tumors). None of 23 undifferentiated or nonkeratinizing NPCs harbored HPV DNA. The putatively oncogenic HPV type 16 may thus be involved in the carcinogenesis of some EBV-negative keratinizing squamous cell nasopharyngeal carcinomas.
Background. Nasopharyngeal carcinoma (NPC) and anaplastic salivary gland carcinoma (SGC), both associated with Epstein‐Barr virus (EBV), are common among Inuit from Greenland, Canada, and Alaska. Because immigrant studies have shown that factors acting early in life are important for the development of NPC, the authors interviewed new patients in Greenland with either NPC or SGC about their lifestyles during childhood and additional cases in their families.
Methods. On admission, new patients from Greenland with either NPC or SGC were interviewed about childhood life‐style, family size, and other cases of NPC or SGC within the family. Additional cases were confirmed by review of the medical records concerning these patients.
Results. During the 11 years from 1980 through 1990, 17 of 63 (27%) cases in Greenland were found in familial clusters among first‐degree relatives. There were no differences in the life‐styles of multiple‐case families and single‐case families.
Conclusions. The high rate of familial clusters among natives of Greenland is of interest because EBV is believed to play a role in the origin of these two diseases similar to that of Marek disease in neurolymphomatosis of chickens. Therefore, the familial clustering of NPC and SGC may indicate that an enhanced oncogenic potential of an EBV strain may occur more frequently in Greenland than in other parts of the world. Cancer 1993; 72:196–200.
The expression of the receptor for epidermal growth factor (EGF) has been determined on oral squamous cell carcinomas. Immunoreactive receptor was localized using a monoclonal anti-EGF-receptor antibody which reacts with sequences in the external domain of the receptor. Frozen sections were studied from 40 patients with squamous cell carcinomas. In 16 sections from the patients with the squamous cell carcinomas, normal differentiated oral mucosa was included and in 7 of these the patients had received preoperative radiotherapy. Sections from 6 other patients with squamous cell carcinoma contained dysplastic epithelia. EGF-receptor-positive cells were present in the basal cell layer on normal differentiated oral mucosa. In sections from patients receiving preoperative radiotherapy the EGF-receptor-positive cells were also found in the spinous cells. In dysplastic epithelia nearly all cells stained for the receptor. The distribution and staining intensity of the EGF receptor varied in the oral squamous cell carcinomas, 36 were positive. The staining pattern in the carcinomas obtained from patients receiving preoperative radiotherapy was not altered qualitatively. Nearly all poorly differentiated cells were stained, but when the tumor was moderately to well differentiated a reduction in the extent of staining in certain areas was seen, paralleling the findings observed in the differentiated upper layers of the normal oral mucosa. This was most pronounced for the epithelial pearls, where the EGF-receptor-positive cells were localized to the undifferentiated cells in the periphery. The results of the present investigation confirm the presence of the EGF receptor on undifferentiated cells, with the extent of the staining reaction on oral squamous cell carcinomas varying inversely with cellular differentiation.
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