Probable mechanism for the loss of Barr body in human female tumor with special reference to breast cancer.

One of the X-chromosomes by a random inactivation process condenses to form X-chromatin (Barr body) in early embryonic life. Once this occurs, it is final and fixed for that cell and all its descendants (1,2). However, numerous investigators have observed extreme variations in Barr body frequency in tumour cells. For example, Sohval and Gains (3) reported an absence of the characteristic Barr body pattern of 19 of the 27 teratomas from females and Moore and Barr (4) observed significant variation in Barr body counts in breast cancer cells. Furthermore, a good correlation was made between the frequency of Barr body and prognosis (5,6,7,8,9). From a retrospective study, it was shown that tumours with low Barr body frequency (BBF) had a significant correlation with blood vessel invasion (BVI) and poor prognosis (10). But the reason why patients with low BBF in the tumor with BVI get early recurrence is not known. In this paper an attempt has been made to suggest a mechanism which may be involved in reducing the BBF with high malignant potentiality.