For some patients, HSCT is an effective treatment for MDS.

Explain how.

MDS can develop from epigenetic changes to tumour suppressor genes. In some patients, the drug AZA has reduced the effects of MDS. AZA is an inhibitor of DNA methyltransferases. These enzymes add methyl groups to cytosine bases.

Suggest and explain how AZA can reduce the effects of MDS in some patients.

The control patients were treated with conventional drugs.

Give two reasons why.

1

2

Use Figure 6 and the information provided to calculate the difference in the number of patients surviving at 10 months after treatment with AZA compared with conventional drugs.