Tumor Molecular Features of Multiple Myeloma Vary by Race/Ethnicity

A single-center study has identified differences in molecular features that may drive clinical disparities seen in patients with multiple myeloma (MM).

According to the study, “MM is twice as common among Black compared to Hispanic and non-Hispanic White individuals, and both Black and Hispanic individuals present with disease at an earlier age than non-Hispanic White individuals.”

To explore these differences and disparities seen in mortality, researchers at Moffitt Cancer Center and Research Institute in Tampa, Florida, studied 495 patients with MM treated at their center. The majority were diagnosed in 2010 or later.

Of these patients, 45 self-reported as Hispanic, 52 as non-Hispanic Black, and 398 as non-Hispanic White. Self-reported race and ethnicity was concordant with genetic ancestry, the researchers noted.

There was a significantly earlier age of onset for Hispanic (53 years) and non-Hispanic Black (57 years) patients compared with non-Hispanic White patients (63 years; P<.001).

The researchers found no differences in treatment received by race and ethnic groups, including frontline therapy or time to drug initiation. However, non-Hispanic Black patients did have a significantly longer time to hematopoietic cell transplant than non-Hispanic White patients (376 vs. 248 days; P=.01).

In contrast, non-Hispanic Black patients had significantly better overall survival (OS) compared with non-Hispanic White patients (hazard ratio [HR]=0.50; 95% CI, 0.31-0.81; P=.005). However, the researchers noted that this difference was attenuated after adjustment for certain clinical features, including age at diagnosis, stage, and treatment (HR=0.62; 95% CI, 0.37-1.03; P=.06).

Molecular features were also studied. Tumor mutations in IRF4 were most common in Hispanic patients, and mutations in SP140, AUTS2, and SETD2 were most common in non-Hispanic Black patients. Differences in expression on BCL7A, SPEF2, and ANKRD26 were also found by race and ethnicity.

Clonal hematopoiesis (CH) was observed in 12% of patients. Non-Hispanic Black patients with CH had worse OS compared with patients without CH (HR=4.36; 95% CI, 1.36-14.00).

“Although we did not observe a difference in frequency of CH by race and ethnicity, differences in the clinical impact of CH by race and ethnicity cannot be ruled out,” the researchers wrote. “Specifically, CH as a predictor of inferior OS in non-Hispanic Black patients with MM and progression-free survival in non-Hispanic White patients with MM warrant further investigation in larger cohorts.”

Peres L, Colin-Leitzinger C, Teng M, et al. Racial and ethnic differences in clonal hematopoiesis, tumor markers, and outcomes of patients with multiple myeloma. Blood Advances. 2022. doi: 10.1182/bloodadvances.2021006652