The malignant cells of most neoplasms show chromosomal abnormalities, and in many the defects are consistent. The most common of the recurring defects is either a band deletion or a reciprocal translocation between two chromosomes.
Using banding techniques, five mixed tumors of the parotid gland were studied in preparations from primary cultures. Two of the tumors had abnormal stemlines. One of them was histopathologically benign and the other one was malignant.
The former showed the karyotype: 46, XX, del (8) (p21), while the latter contained pseudohypotetraploid stem line, mn: 87, about 25% were marker chromo-somes.
The results are discussed in relation to the previously existing sparse data available on mixed salivary gland tumors and their relationship to the possible general significance of chromosome changes affecting No. 8.
