Abstract

Sex chromatin studies on squash preparations of a well differentiated transitional cell carcinoma of the bladder without evidence of invasion from a female aged 63 revealed a single body in some regions, but two to four bodies in others. All regions were near diploid according to DNA estimations. Previous observations on a variety of invasive tumours of females showed that the presence of more than one sex chromatin body is generally associated with a high chromosome number. The pattern of two or more bodies in near-diploid cells seen in this non-invasive tumour may therefore characterize an intermediate stage of clonal evolution, eventually resulting in malignancy, when the cell line has not yet achieved the ability to invade or metastasize.