Differentiation-inducing liposoluble vitamin deficiency may explain frequent secondary solid tumors after hematopoietic stem cell transplantation: minireview.

Secondary cancers are among the most threatening long-term health problems of hematopoetic stem cell- transplant (HSCT) patients. There are several lines of evidence indicating the possibility of a prolonged Vitamin A deficiency for solid tumor-type secondary cancers: I- Solid tumors such as oral cavity, head/neck region squamous carcinomas, skin cancers and melanomas, where lowered Vitamin A concentrations and chemo-preventing activity of its derivatives (retinoids) are most explicitly proven, arise much more frequently than others. II- Early monitorings: A significant retinol deficiency in HSCT patients is detectable along with a severity of mucositis and the vulnerability to infection. III- Monitoring of other liposoluble vitamins: Vitamin D, a differentiation-inducing vitamin like Vitamin A, showed a sustained decrease. Another similarity of these two vitamins is that they also depend on intestinal absorption and are decreased due to bowel injury by conditioning agents and chronic graft-versus-host disease. IV- Peroxidative reactions and inflammation can directly exhaust retinol levels despite sufficient intake. Considering the similar inhibitory role of Vitamin D analogs (deltanoids) on squamous carcinomas, skin tumors and melanomas, we propose that animal studies and extended vitamin surveillance studies in HSCT patients may unfold a preventive strategy against long-term complications.