Microcephalin guards against small brains, genetic instability, and cancer.

Through its roles in cell cycle control and DNA damage response, microcephalin (also known as BRIT1 or MCPH1) has been implicated in fundamental biological processes, including regulation of brain size and maintenance of genomic integrity. Two new reports in Nature Cell Biology and this issue of Cancer Cell provide further insights into the functions of microcephalin in DNA damage checkpoints and timing of mitosis. Depletion or disease-associated mutations of microcephalin resulted in centrosomal abnormalities and chromosomal instability. These findings and aberrantly reduced expression in human carcinomas identify microcephalin as a candidate novel tumor suppressor.