Copy number gain in chromosome 8q21 is considered as the prototype of genetic abnormalities associated with development of breast cancer, yet the oncogenic potential underlying this amplicon in breast carcinogenesis remains to be delineated. We report here that ZNF704, a gene mapped to 8q21, is recurrently amplified in breast cancer. We found that ZNF704 acts as transcription repressor and interacts with the transcription corepressor SIN3A complex. Genome-wide interrogation of the transcriptional targets identifies that the ZNF704/SIN3A complex represses a panel of genes including PER2 that are critically involved in the function of circadian clock. Indeed, ZNF704 overexpression prolongs the period and dampens amplitude of circadian clock. We showed that ZNF704 promotes the proliferation and invasion of breast cancer cells in vitro and accelerates the growth and metastasis of breast cancer in vivo. Consistently, the level of ZNF704 expression is inversely correlated with that of PER2 in breast carcinomas, and high level of ZNF704 correlates with advanced histological grades, lymph node positivity, and poor prognosis of breast cancer patients, especially those with HER2+ and basal-like subtypes.

Circadian Rhythm Is Disrupted by ZNF704 in Breast Carcinogenesis