Scientists here solve leukaemia puzzle

Mutant nucleophosmin proteins (green) are the culprits behind chromosomes that look normal in acute myeloid leukaemia cancer cells.
Mutant nucleophosmin proteins (green) are the culprits behind chromosomes that look normal in acute myeloid leukaemia cancer cells.PHOTO: NARISA CHAN

Singapore scientists have found what causes one in three patients who suffer from acute myeloid leukaemia to possess cancer cells with normal instead of abnormal-looking chromosomes.

The culprit is mutated nucleophosmin (NPM) proteins, which help prevent unequal segregation of chromosomes during cell division, said the study's leader, Professor Lim Tit Meng of the National University of Singapore's Department of Biological Sciences.

Each normal human cell has 23 pairs of chromosomes. In cancer cells, the number and structure of these chromosomes are typically abnormal.

When this happens, it could lead to genomic instability, which is linked to the formation of tumours.

Normal-looking chromosomes in acute myeloid leukaemia cancer cells had hence left scientists puzzled, before Prof Lim and his team discovered that mutated NPM proteins were the culprits behind the phenomenon.

But more importantly, mutated NPM proteins have been found to cause cancer by inhibiting cell death and cell differentiation.

This was uncovered in earlier research that was also led by Prof Lim.

Acute myeloid leukaemia is the most common form of cancer of the blood and bone marrow.

It rears its ugly head when the blood cells created by the body become abnormal.

This includes red blood cells that carry oxygen to tissues in the body, white blood cells that fight infection and platelets that stop bleeding by clotting blood.

According to the Ministry of Health, about 100 people in Singapore were diagnosed with it each year between 2010 and 2014. The average age of the patients was 58 years.

This latest finding, published in the international journal Scientific Reports, reinforces the potential of using NPM proteins as a drug target to treat patients with acute myeloid leukaemia, said Prof Lim.

Samantha Boh

A version of this article appeared in the print edition of The Straits Times on December 04, 2015, with the headline 'Scientists here solve leukaemia puzzle'. Print Edition | Subscribe