Relatives of Patients with Myeloid Blood Cancer at Two-Fold Risk of Disease

A team of scientists at The Institute of Cancer Research (ICR), in London, England, and the German Cancer Research Centre in Heidelberg, Germany, have found that relatives of individuals with certain types of blood cancer may harbor inherited genetic changes that could influence their risk of developing diseases that arise from myeloid cells.

The investigators postulate that their findings could assist in identifying individuals at greatest risk of these diseases and where genetic testing, medical observation, and counseling could be beneficial in the future. The data may also lead to new research that could decipher the genetic causes of myeloid blood cancers.

"Our study provides the strongest evidence yet for inherited risk for these diseases—evidence that has proved evasive before in part because these cancers are relatively uncommon, and our ability to characterize these diseases has, until recently, been limited,” said lead author, Amit Sud, MBChB (Hons), MRCP, PhD, clinical research fellow at the Institute of Cancer Research, in a recent statement.

In an effort to discover whether an increased risk of blood cancers existed in relatives of patients, Dr. Amit and his team evaluated information pertaining to every patient diagnosed with myeloid diseases in Sweden, according to ICR. For their study, published in the journal Blood, the investigative team compared the occurrence of myeloid-type cancers and related diseases diagnosed in over 35,000 patients and 93,000 family members with cases diagnosed among the general population.

Overall, the team found that individuals were about twice as likely to develop myeloid diseases as those without a family history of the disease. Furthermore, they found that compared with someone from the general population, a first-degree relative of someone with myelodysplastic syndrome had around a 7-fold risk of developing the disease.

Investigators reported that risk varied depending on the type of disease. For instance, the standardized incident ratio (SIR) for first-degree relatives of patients with myeloproliferative neoplasm (MPNs) was 4.93%. For other myeloid cancers, the SIR was even higher; for polycythemia vera it was 7.66%, for essential thrombocythemia it was 6.75%, and for myelodysplastic syndrome it was 6.88%. Lower SIR values were noted for first-degree relative of patients with myeloid malignancies (1.99%), chronic myeloid leukemia (0.78%), acute myeloid leukemia (1.53%).

In all the disease types, the risk of first-degree family members developing the disease increased by up to 5 times if 2 or more documented cases of myeloid diseases existed within the family. Having a parent diagnosed with the disease at a relatively young age was an indicator of higher risk for relatives developing the disease.

The investigators concluded that the risk of myeloid cancers is passed on through families and is most likely to be attributed to inherited genetic traits passed on in DNA. However, the investigators noted that environmental factors shared in families could also play a role.

"In the future, our findings could help identify people at higher risk than normal because of their family background, who could be prioritized for medical help like screening to catch the disease earlier if it arises,” Dr. Amit said.