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BACKGROUND A fluorescence in situ hybridization (FISH) technique using specific DNA probes allows for the detection of chromosomal aberrations and gene deletions and gains, even in interphase nuclei in human solid tumors. A high frequency of aberrations of chromosome 17 and mutation of the p53 gene have been reported in some human tumors. The correlation of p53 expression with abnormalities of chromosome 17 and p53 gene deletion in salivary gland tumors has not yet been investigated. METHODS The authors analyzed the numeric aberrations of chromosome 17 and p53 gene deletions in 11 paraffin embedded pleomorphic adenomas (PA) and 9 carcinomas in pleomorphic adenoma (CIPA), using FISH techniques. The centromere specific DNA probe for chromosome 17 and p53 cosmid DNA probe was used. The aberrations of chromosome 17 and p53 deletions were correlated with immunohistochemical detection of p53 protein. RESULTS Monosomy 17 was detected in 30.8% of CIPA cells and 29.6% of PA cells, and polysomy 17 was detected in 19.6% of CIPA cells and 9.6% of PA cells. p53 protein expression was observed in 6 of 9 CIPA specimens (66.7%) and 2 of 75 PA specimens (2.7%). Deletion of the p53 gene was frequent in p53 protein positive specimens. A statistically significant correlation existed between p53 protein expression and polysomy 17 (P = 0.0417). CONCLUSIONS It was observed that loss of chromosome 17 may occur in PA before its transformation to carcinoma. p53 expression was frequently associated with deletion of the p53 gene as detected by FISH. Polysomy 17 was more frequent in CIPA than PA and was associated with mutation of p53. Cancer 1997; 79:2314‐9. © 1997 American Cancer Society.

The relationship between labeling indices of Ki-67 reactive antigen expressed by cycling cells and BrdUrd incorporated into S-phase cells was investigated in 20 patients with malignant tumors. Both of the labeling indices varied greatly from patient to patient; the labeling index of Ki-67 ranged from 37.5% to 1.9% with an average value of 16%, and the BrdUrd labeling index ranged from 23.4% to 1.6% with an average of 9.3%. The Ki-67 labeling index was higher than the BrdUrd labeling index. In general, the values of the Ki-67 labeling index were parallel to those of the BrdUrd labeling index, and the relation Y = 1.59X + 1.15 (r = 0.89) was obtained. In human solid tumors, therefore, the growth fraction can be easily estimated from the S-phase fraction size, and vice versa.

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