Human fork head Box C1 is a gene which belongs to the forkhead family. These are the transcription factors that are characterized by their distinct DNA binding forkhead domain. None of their specific functions are determined yet, but it has been shown that it plays a role in embryonic and ocular development regulation. Various glaucoma phenotypes which include autosomal dominant iridogonidoysgenesis anomaly, congenital glaucoma and Axenfeld-Rieger anomaly are known to be associated with mutations in Human forkhead Box C1 gene. Recently, Forkhead Box transcription has been used as a diagnostic marker for Basal- like Breast Cancer.

A two tier assay which is based on forkhead box C1 identified Basal like Breast cancer accurately. The accuracy of Forkhead Box C1 was compared with PAM50 gene expression in the microarray. A forkhead box C1 based assay was simple, fast, cost-effective and accurate and can emerge as a diagnostic assay for basal like breast cancer. Forkhead Box C1 results in expression of MMP7 without decreasing the expression of matrix metalloproteinases in basal like breast cancer cell lines. Matrix metalloprotease 7 (MMP 7) is a downstream effector of forkhead box C1 related invasiveness. The function of forkhead box C1 is associated with hundreds of genes which change their expression patterns based on the changes in expression of forkhead box C1. Forkhead Box C1 is also involved in DNA binding and folding. Binding of fork head proteins in their associated sites leads to DNA bending at 80-90 degrees which enhances transcriptional activity of some genes.  Cytoplasmic protein p32 regulates the Forkhead box C1 protein in ocular cells. Forkhead Box C1 and forkhead Box C2 regulates the paraxial establishment versus intermediate mesoderm cell fates in embryos of vertebrates. Forkhead box C1 and forkhead box C2 are important in development processes of urinary tract, kidney and heart.