Cytogenetic observations on two ovarian carcinomas with double minutes, one with a 6q- marker chromosome.

A high number of structurally altered marker chromosomes was found in two cases of ovarian carcinoma. Even by the application of different staining methods it was not possible to identify all the chromosomes. No evidence for the existence of a translocation between chromosomes 6 and 14 was found, which seems to be a specific abnormality characteristic of papillary serous cystadenocarcinomas of the ovary. It is of interest that double minutes were present in both cases. This offers further evidence for the assumption that double minutes are not infrequent in carcinomas. Their orthodox mitotic behaviour leads to high karyotype variability (number of double minutes/cell), and may be of particular importance for tumour biology. The methodological and cytogenetic implications of the results are discussed.