STUDY LINKS Y CHROMOSOME LOSS TO EARLY CANCER WARNING SIGNS

A study from the University of Arizona Cancer Centre has found that loss of the Y chromosome in men's tissue may be an early sign of cancer development, the researchers reported in JCI Insights. Dr Dan Theodorescu, the senior author, said the change creates a "preneoplastic field effect" — a hidden zone of genetic vulnerability in normal-looking tissue. Human cells carry one X and one Y chromosome, and loss of the Y chromosome becomes more common as men age. Theodorescu said the loss was found in normal-appearing tissue next to tumours, calling it one of the earliest signs of cancer forming.

The team analysed 1,000 tissue samples from 405 men across 11 major organs, using fluorescent imaging to examine more than 4.3 million cell nuclei and measure the ratio of Y to X chromosomes. Earlier research had linked loss of Y in blood cells to a higher risk of disease, but this study extended the analysis to normal, precancerous and cancerous tissue. Researchers also mapped bladder tissue removed during cancer surgery. The maps showed loss of Y increasing as cells moved from normal tissue through early abnormal changes and into cancer.

The loss of Y in normal-appearing tissue was highest in samples linked to colon, rectal, oesophageal, pancreatic and lung cancers, the study found. Theodorescu likened the pattern to "a hillside that slowly gets steeper," saying tissue closer to a tumour showed greater loss of the Y chromosome. The researchers said this pattern, observed consistently across the 11 organs studied, suggests the chromosome loss could serve as one of the earliest identifiable markers of tumour formation. Theodorescu is also a professor at the University of Arizona College of Medicine in Tucson.