A study published in the journal Blood suggests that certain myeloma growth factors may one day serve as a target for therapies. This particular study found significant results pertaining to insulin-like growth factor type 1, or IGF-1.

IGF-1 is a molecule produced in bone marrow that binds to the IGF-1 receptor (IGF-1R), if present. Binding sets off a cascade of molecular events that ultimately stimulates cell growth. Many myeloma growth factors exist, and this study investigated five.

Using cell lines derived from human myeloma cells, the researchers found that of the five growth factors studied, IGF-1 significantly stimulated the growth of myeloma cells, as did interleuken-6 (IL-6).

The finding supports several other studies, and the researchers suggest that a therapy that inhibits IGF-1R could be useful in patients whose cells express the receptor. Normal immune system cells do not express the IGF-1R gene, but it is found in 30 to 50 percent of untreated myeloma patients.

In the second part of the study, the researchers found that the presence of IGF-1R correlated with poor prognosis in myeloma patients. Patients without IGF-1R had a longer median event-free survival and overall survival than patients with IGF-1R.

The researchers emphasize that the study does not suggest that presence of IGF-1R can be useful in defining new classifications for prognosis. Instead, they maintain that because the presence of IGF-1R in myeloma cells is correlated with poor prognosis, targeting IGF-1R could be promising for the treatment of myeloma patients.

For further details, see the article in the journal Blood ^[1] (subscription required for full article; abstract available for free).