X-chromosomal Inactivation Skewing Of Blood Cells Is Associated With Early Development Of Lung Cancer And Esophageal Cancer In Females

Random X-chromosome inactivation, also known as Lyonization, results in the transcriptional silencing of almost all genes located in one of the two X chromosomes of diploid female cells. It occurs during the interphase early in embryogenesis when one X chromosome is randomly inactivated by extensive methylation and condensation to form the sex chromatin body. The remaining, uncondensed one becomes the active X chromosome and is inherited by all daughter cells through subsequent mitotic division. Because this process is random, adult female tissues are cellular mosaics, wherein half of the cells contain an active maternal X chromosome (Xm) and the other half contain an active paternal X chromosome (Xp).Theoretically, the ratio of the paternal inactive X-linked allele to maternal one should be 1:1, and any significant deviation from the ratio is termed as skewed X chromosome inactivation (SXCI). Lyonization ratio (inactive Xp/Xm) of a large population of females follows a Gaussian distribution pattern in which SXCI is a statistically rare event. The recent surveys have associated SXCI to the development...