Background: We were interested to know why cancer patients are frequently associated with elevated circulating total homocysteine (tHcy) even though they are not treated with anti-folate drugs.
Methods: We employed tissue cultures to compare both the homocysteine (Hcy)-released and production of tumor markers between tumor and normal cell lines.
Results: We detected much higher concentrations of homocysteine (Hcy) released by the tumor cells. However, much less difference was found between normal and tumor cell lines when Hcy concentration was expressed per the same number of cells. During the cell culture, the increase of Hcy and the increase of tumor marker concentration paralleled each other for the first 7 days. After the seventh day of the culture when cells started dying, tumor markers continued to rise, whereas levels of Hcy and cell numbers leveled off. We found that the serum concentration of Hcy fluctuated in circulation coinciding with that of tumor marker in individual cancer patients unless taking anti-neoplastic drug.
Conclusions: The elevation of tHcy concentration may be caused by the rapid tumor cell proliferation and reflect only the number of live cells. Serum Hcy may be a potentially useful tumor marker to monitor tumor activity.