Identical chromosome translocations involving the region of the c-myb oncogene in four metastases of a mediastinal teratocarcinoma

A 39-year-old white male presented with a disseminated mediastinal teratocarcinoma. Karyotyping was performed on two mature residual metastatic lesions in the lungs immediately following chemotherapy, on a recurring lung lesion after 5 months, and on a metastasis in the right thigh 5 months after salvage chemotherapy. All four lesions were pseudoeuploid and showed identical chromosomal abnormalities: a translocation with the two chromosomes #6 and one chromosome #11 involved, resulting in 46, XY, t (6;6;11) (q21;q23;q13). The breakpoint in chromosome #6 is in the region to which the oncogene c-myb has been localized, and the breakpoint in chromosome #11 is at a known fragile and possibly oncogenic site, suggesting that the translocations in this case may have played a crucial role in the development of the malignancy.