Association of insulin like growth factor-1 (IGF-1) and thyroid hormones in patients of acute leukemia

For many years, several studies have demonstrated a relationship between insulin like growth factor-1 (IGF-1), thyroid hormones, and various malignancies. IGF-1 plays an important role in tumor proliferation in various malignancies. The relationship between IGF-1 and thyroid hormones is complex and not fully understood. Therefore we planned to evaluate the level of IGF-1 and thyroid hormones in patients of acute leukemia.

The present study included 25 patients with acute leukemia (Acute Myeloid Leukemia, n = 16; Acute Lymphoid Leukemia n = 9, mean age 28.16 years). 25 age and gender matched healthy individuals were taken as control (mean age 27.17 years). In all the subjects, serum IGF-1 was measured by enzyme linked immunosorbent assay (ELISA), serum total triiodothyronine (T3), thyroxine (T4) by radioimmunoassay (RIA), thyroid stimulating hormone (TSH) by immunoradiometric assay (IRMA), and free T3 (FT3) and free T4 (FT4) by chemilluminiscence. These tests were done before starting of chemotherapy and either 6 to 8 weeks after chemotherapy or at the time of remission, whichever was earlier.

At the time of diagnosis, patients with acute leukemia showed a significantly increased level of IGF-1 as compared to controls (198.32 +/- 67.55 vs 160.64 +/- 45.96; p < 0.01). After 6 to 8 weeks of chemotherapy, patients with acute leukemia showed a significant decrease in the level of IGF-1 compared to the baseline values (198.32 +/- 67.55 vs 155.6 +/- 45.96; p < 0.01). Though FT3, FT4, total T3, and total T4 values in these patients were within the normal range, these values were still significantly higher compared to controls. TSH levels were significantly lower in patients at the time of presentation and the levels increased after chemotherapy.

The estimation of IGF-1 and thyroid hormones may be helpful in assessing the disease activity and predicting the response of chemotherapy.