Evaluation of Serum Vitamin B12 Levels in Patients with Colon and Breast Cancer: A Case-Control Study.

It has been shown that increased serum levels of vitamin B12 may be associated with some malignancies. This study aimed to compare the serum levels of vitamin B12 in patients with colon and breast cancer and healthy individuals. In this case-control study, 140 patients with colon and breast cancer were compared with 140 healthy individuals matched in age, gender, and socioeconomic status. Serum levels of vitamin B12 were measured through the Electrochemiluminescence method in both groups. The normal serum level of vitamin B12 was between 200 and 800 pg/ml. Among 280 enrolled subjects, 60 had serum vitamin B12 levels higher than 800 pg/ml. Forty-six (32.9%) patients had high serum vitamin B12 levels, compared to 14 (10.0%) subjects in the control group (P = 0.001). The mean serum vitamin B12 level was significantly higher in the patients (380.4 ±540.2 pg/ml vs. 278.0 ±314.08 pg/ml, P =0.001). There was no statistically significant difference in serum levels of vitamin B12 in patients with breast and colon tumors (P = 0.8). A significant positive correlation was observed between serum levels of vitamin B12 and tumor stage (P = 0.001, r = 0.49). The findings of this study showed that serum levels of vitamin B12 in patients with colon and breast cancer are higher than in healthy individuals and are positively associated with the stages of cancer.