Colorectal cancer, one of the most common cancers in the developed world, is intrinsically resistant to many drug therapies. In an attempt to identify novel treatment strategies, researchers examined the contribution of serine racemase (SRR) to colorectal cancer metabolism. The researchers showed that SRR is required for cancer cell proliferation, and that inhibition of SRR in mice halted tumor progression, paving the way for future drug development.