The recent spotlight on the role of the Y chromosome in cancer outcomes has unearthed important findings. Primarily, it has emphasized the marked vulnerability of males to certain types of cancer. These studies, focusing on colorectal and bladder cancer, have brought forward crucial genetic mechanisms that contribute to tumour progression, immune response, and clinical prognosis.
Colorectal and Bladder Cancer: An Overview
Cancer, a broad and complex term, describes a variety of diseases defined by the uncontrolled growth and dissemination of abnormal cells within the body. These cells, otherwise known as cancer cells, have the potential to invade and destroy healthy tissues and organs.
Colorectal Cancer, also known as colon or rectal cancer, develops in the large intestine. It begins as small, noncancerous growths called polyps found on the inner lining of the colon or rectum. Over time, these can turn malignant. On the other hand, bladder cancer involves the development of cancerous cells in the urinary bladder, the organ responsible for storing urine.
Study Findings: Role of the Y Chromosome in Colorectal Cancer in Males
Investigations into sex differences in colorectal cancer using a mouse model highlighted a high frequency of metastasis and decreased survival rate in male mice, thereby mirroring human outcomes. Researchers also identified an upregulated gene on the Y chromosome that contributes to colorectal cancer in males by driving tumour invasion and fostering immune escape.
This gene activates those genes that promote cell migration, invasion, and angiogenesis (formation of new blood vessels). Simultaneously, it suppresses the genes that trigger immune response.
Impact of Y Chromosome Loss on Bladder Cancer Outcomes
A separate examination revealed the effects of Y chromosome loss on bladder cancer outcomes. As men age, Y chromosome loss can occur, allowing cancer cells to evade their immune systems. The loss of the Y chromosome links with poor diagnosis and aggressive tumours.
Remarkably, this condition creates a more immunosuppressive tumour microenvironment by altering the expression of genes related to immune regulation. Loss of Y chromosome enhances the response to Anti-PD1 Checkpoint Blockade Therapy, suggesting a potential treatment avenue for some bladder cancers.
Understanding Chromosomes
A chromosome is a thread-like structure comprising nucleic acids and proteins found in the nucleus of most living cells. These carry genetic information in the form of genes and play a crucial role in cell division, growth and development, and inheritance.
Chromosomes consist of DNA molecules tightly wound around proteins called histones. This combination helps compact and organise the genetic material. In humans, each cell contains 23 pairs of chromosomes.
There are two main types of chromosomes: autosomes and sex chromosomes. Autosomes are non-sex chromosomes which determine various traits and characteristics, excluding those related to sex determination. Sex chromosomes, represented by X and Y, determine the sex of an individual. Females have two X chromosomes, whereas males have one X and one Y chromosome.
