CCDC6 encodes a coiled-coil domain-containing protein that is ubiquitously expressed and may function as a tumor suppressor. CCDC6 is an ATM substrate involved in genotoxic stress response and maintaining genome stability. It negatively regulates PPP4C enzymatic activity as part of the response to DNA damage. A chromosomal rearrangement resulting in the expression of a fusion gene containing a portion of this gene and the intracellular kinase-encoding domain of the RET proto-oncogene is the cause of thyroid papillary carcinoma. In immunohistochemistry of normal tissue, CCDC6 has cytoplasmic positivity in most tissues, with strongest expression in fallopian tubes. References: PLoS One. 2012; 7(5): e36177, PMID: 22655027; The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804