Cytogenetic preparations and Feulgen stain of tumor tissue were applied to the question of the relationship between the sex (X) chromatin body and the X-chromosome constitution of tumor cells. The data revealed that in Case 1, a malignant mesonephroma, the tumor was hyperploid and that there was no loss of the C + X group of chromosomes. Nevertheless, not a single X-chromatin body was encountered among one thousand tumor epithelial cells. Stromal cells within which the tumor was embedded, nonmalignant mesonephric epithelium, and its normal stroma showed 20% X-chromatin positive cells. It is concluded from this and correlative data from a second case similarly analyzed, that the condensation of the heteropyknotic X is not fixed. Rather, under appropriate conditions, such as in neoplasia, it is reversible. As the euchromatic state of the X-chromosomes is characteristic of the oogonium and the cleavage stage of the embryo, this process may be viewed as chromosomal dedifferentiation.

1

This work was made possible in part by Grant CA 08791-02 from the NIH, and research fellowships established in the names of Louis Issikman, Max R. Eisman, and Paul W. Priddy.

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©1969 American Association for Cancer Research.
1969
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