DHRS9 and cancer: Next to increased OXPHOS and GSH stabilization, vitamin A (retinol) metabolism and its final metabolite all‐trans retinoic acid (ATRA), associated with cancer cell proliferation [40], might potentially be yet undescribed regulators for metastatic brain tropism as suggested by upregulated DHRS9 and CYP26B1 specific for CNS‐resident CRC metastases.