Archives for posts with tag: cytogenetics

Susan Sontag survived uterine and breast cancer, but as sometimes happens, the treatment that cured her eventually caused the MDS that killed her (“therapy-related MDS” or t-MDS). Her son David Rieff gives some insight into her illness in his book Swimming in a Sea of Death: A Son’s Memoir (Granta). After a bone marrow transplant, her disease became full-blown leukaemia. (Not all cases of MDS are this severe.)

File:Susan Sontag by Juan Bastos.JPG
Susan Sontag by Juan Fernando Bastos, CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons.

Chromosome analysis of the MDS cells is one of the tests used to predict the patient’s outlook. “The spectacularly difficult cytogenetics of her specific case” (very abnormal chromosomes), as Rieff puts it, means she had a poor chance of survival.

Sontag stands out as a patient because she wrote about illness, in her philosophical book Illness as Metaphor. I came across the story of her treatment and one of her quotes about illness in Siddhartha Mukherjee’s very readable book, The Emperor of All Maladies: A Biography of Cancer.

“Illness is the night-side of life, a more onerous citizenship. Everyone who is born holds dual citizenship, in the kingdom of the well, and in the kingdom of the sick. Although we all prefer to use only the good passport, sooner or later each of us is obliged, at least for a spell, to identify ourselves as citizens of that other place.”

Susan Sontag, Illness as Metaphor. Published by Farrar, Straus and Giroux (1978)

25th October is World MDS Awareness Day. This article is part of a series about high-profile MDS patients.

Other stories:

MDS and the Fantastic Mr Dahl

Carl Sagan’s Last Project

The 14th July is the Leukaemia Foundation of Australia’s annual National MDS Day.

Myelodysplastic Syndromes (MDS) make up a group of diseases that have abnormal blood cell production. MDS is sometimes called pre-leukemia because about a third of patients with MDS will develop leukemia.

MDS is caused by errors in the bone marrow’s genetic information. These errors can often be seen down the microscope as changes to the chromosomes. MDS patients typically have their bone marrow cells analysed to find chromosome abnormalities. Why?

These chromosome abnormalities can reveal important information about their disease, such as diagnosis, appropriate treatment and prognosis.

The IPSS-R is a system that’s used to work out prognosis for MDS patients – that is, how they will do – what their health outlook and risk of developing leukaemia are. A prognostic score is a number calculated from different aspects of the disease. A low score indicates low risk and risk increases as the score goes up. Cytogenetics, or chromosome analysis, is needed to calculate this score because “chromosome abnormalities” is one of the five categories used in the calculation.

For example, if the cells are missing a Y chromosome nothing is added to the IPSS-R prognostic score, whereas if four or more chromosome abnormalities are found, 4 points are added to the score, which can almost single-handedly take the disease into the high (4.5-6) or very high (over 6) risk category.

del20q

Normal chromosome 20 (left) and abnormal chromosome 20 missing most of the long arm (“del(20q)”).

 

The abnormal chromosome pictured on the right is a deleted chromosome 20  – it’s lost a big chunk carrying hundreds of genes. This is one of the well-known chromosome abnormalities in MDS. We can work out which genes have been lost using higher resolution molecular analysis, but this is not necessary for calculating the IPSS-R prognostic score. One point is added to the score if there’s a deleted chromosome 20 and it’s the only chromosome abnormality. It’s one of the chromosome abnormalities in the “good” cytogenetic category.

So chromosome analysis is an important piece of the puzzle in the care of MDS patients.

More information:

The IPSS-R http://www.bloodjournal.org/content/120/12/2454?sso-checked=true

MDS Foundation – What is MDS? http://www.mds-foundation.org/what-is-mds/

The MDS Beacon http://www.mdsbeacon.com/

Previous MDS Day posts:

Carl Sagan’s Lasts Project – Overcoming MDS

MDS and the Fantastic Mr Dahl

What does IPSS-R stand for? Revised International Prognostic Scoring System for Myelodysplastic Syndromes.

Cross-posted to Fireside Science on the SciFund Challenge network