Higher Body Mass Index Accelerates Growth of Multiple Myeloma

In a study published in Cancer Letter, researchers found that as body mass index (BMI) increases, so too does the growth and spread of multiple myeloma (MM).

“Once a person with cancer is out of the normal weight category, their BMI is contributing to multiple myeloma growth and progression,” said lead study author Katie DeCicco-Skinner.

Findings from prior studies suggest that obesity is a risk factor for numerous cancers, and that each 5 kg/m2 increase in BMI is associated with an increase of 10% in cancer-related deaths. In the current study, researchers studied BMI in normal, overweight, obese, and morbidly obese patients, to evaluate the effect on MM.

Normal weight was defined as a BMI of no more than 25 kg/m2, with morbidly obese ranging from 35 to 40 kg/m2. Stem cells were obtained from the discarded fat of liposuction patients who had undergone elective surgery.

Researchers turned them into fat cells and cultured the cells with multiple myeloma. The results of the study showed that as a patient’s BMI increases, the fat cells communicate with MM cells.

The fat cells then began to grow, gain additional lipid, and secrete proteins linked to cancer. Additionally, researchers found a correlation between BMI and key indicators of progression: angiogenesis and adhesion.

“We know multiple myeloma cells will anchor into bone marrow, and fat cells in the bone marrow will support the growth and spread of the cancer,” DeCicco-Skinner said. “In our study, as BMI increased, we started seeing an increase in the ability of multiple myeloma cells to adhere, which causes the cancer to better anchor. With angiogenesis, cancer cells cannot exist without their own blood supply. We also found the amount of blood vessels that developed was directly proportional to a patient’s BMI.”

Although the researchers assumed that cancer proliferation benefits from higher-than-normal BMI due to the epidemiological link between cancer and obesity, they were surprised by the drastic relationship between MM and the BMI of obese and morbidly obese patients.

“We found that fat cells from obese or morbidly obese patients secreted a high amount of inflammatory proteins, which contribute to tumor progression,” DeCicco-Skinner said.

The findings suggest a potential new approach for the treatment of MM. Authors noted that physicians should consider tailoring drugs based on patient BMI since certain drugs may not be as effective in patients who are obese or morbidly obese.

“Most people think if you develop multiple myeloma, you go to the doctor, find out what the most effective drug cocktail is and how it will affect you,” DeCicco-Skinner said. “A patient may need to receive drugs to block inflammatory or other obesity-specific proteins, in addition to standard anti-cancer drugs they receive. Obesity increasingly plays a role in cancer cases as the numbers of those who are obese rise. Improving our understanding of how fat cells and cancer cells communicate with each other, and how the communication changes during obesity, is critical.”