Influence of Y Chromosome on Cancer Outcomes

• 27 Jun 2023

For Prelims: Colorectal Cancer, DNA , T cell , Biomarker, Chromosomes.

For Mains: Impact of Y Chromosome on Cancer Outcomes.

Why in News?

Recent studies have provided insights into the influence of the Y chromosome on cancer outcomes, highlighting the greater vulnerability of males to certain types of cancer.

• These studies shed light on the role of the Y chromosome in colorectal and bladder cancer, revealing key genetic mechanisms that contribute to tumour progression, immune response, and clinical prognosis.

What is Colorectal and Bladder Cancer?

• About Cancer:
  • Cancer is a complex and broad term used to describe a group of diseases characterised by the uncontrolled growth and spread of abnormal cells in the body.
    • These abnormal cells, known as cancer cells, have the ability to invade and destroy healthy tissues and organs.
  • In a healthy body, cells grow, divide, and die in a regulated manner, allowing for the normal functioning of tissues and organs.
    • However, in the case of cancer, certain genetic mutations or abnormalities disrupt this normal cell cycle, causing cells to divide and grow uncontrollably.
    • These cells can form a mass of tissue called a tumor.
• Colorectal Cancer:
  • Colorectal Cancer, also known as colon cancer or rectal cancer, refers to cancer that develops in the colon or rectum, which are parts of the large intestine.
    • It is one of the most common types of cancer worldwide.
  • It typically begins as small, noncancerous growths called polyps on the inner lining of the colon or rectum. Over time, some of these polyps can develop into cancer.
• Bladder Cancer:
  • Bladder cancer refers to the development of cancerous cells in the tissues of the urinary bladder, the organ responsible for storing urine.

What are the Major Findings of the Study?

• Role of the Y Chromosome in Colorectal Cancer in Males:
  • Studies investigated the sex differences in colorectal cancer using a mouse model driven by a known oncogene called KRAS.
    • They found that male mice had a higher frequency of metastasis (spread of cancer cells from the original site of a tumor to other parts of the body) and worse survival than female mice, mirroring the outcomes seen in humans.
  • They also identified an upregulated gene on the Y chromosome that contributes to colorectal cancer in males by driving tumour invasion and aiding immune escape.
    • It leads to the activation of genes that promote cell migration, invasion, and angiogenesis (the formation of new blood vessels), as well as the suppression of genes that stimulate immune response.

Note: KRAS is a gene that encodes a protein called Kirsten Rat Sarcoma Viral Oncogene Homolog. It is a proto-oncogene, meaning that it has the potential to become a cancer-causing gene.

• Impact of Y Chromosome Loss on Bladder Cancer Outcomes:
  • In a separate investigation, the impact of Y chromosome loss on bladder cancer outcomes was observed.
    • Loss of the Y chromosome in cells happens as men age, enabling cancer cells to evade their immune system
  • Loss of the Y chromosome was found to be associated with poor diagnosis and more aggressive tumours.
    • The condition generated a more immunosuppressive tumour microenvironment by altering the expression of genes involved in immune regulation.
    • For instance, loss of the Y chromosome increased the expression of PD-L1, a protein that inhibits T cell activation and allows tumour cells to evade immune attack.
  • However, Y chromosome loss was found to enhance the response to Anti-PD1 Checkpoint Blockade Therapy, suggesting a potential treatment avenue for a subset of bladder cancers.
    • This suggests that loss of the Y chromosome may be a biomarker for selecting patients who may benefit from this treatment.

What is a Chromosome?

• About: A chromosome is a thread-like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
  • Chromosomes are essential for cell division, growth and development, and inheritance.
  • In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46.
• Structure: Chromosomes are composed of DNA molecules that are tightly wound around proteins called histones.
  • This combination of DNA and proteins helps to compact and organise the genetic material.
• Types: There are two main types of chromosomes: autosomes and sex chromosomes.
  • Autosomes: Autosomes are non-sex chromosomes.
    • In humans, there are 22 pairs of autosomes, numbered from 1 to 22.
    • Autosomes contain genes responsible for determining various traits and characteristics, excluding those related to sex determination.
  • Sex chromosomes: Sex chromosomes determine the sex of an individual and are represented by the letters X and Y.
    • In humans, females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).

UPSC Civil Services Examination, Previous Year Question (PYQ)

Q. Which one of the following statements best describes the role of B cells and T cells in the human body?(2022)

(a) They protect the environmental allergens. body
(b) They alleviate the body’s pain and inflammation.
(c) They act as immunosuppressants in the body.
(d) They protect the body from diseases caused by pathogens.

Ans: (d)

Source: IE