PIK3CA and head and neck cancer: For instance, Ibrahimovic et al. [271] report that hsa-miR-7-1 and hsa-miR-335, i.e., two oncogenic molecules known to play roles in head and neck cancer or precursor lesions, were modulated by vitamin D3; they were significantly down-regulated in two human HNC cell lines of squamous cell origin, CAL-27 and SCC-25, and acted through multiple pathways relevant to HNCs, including MAPK, PI3K, RAS, and chemokine signalling.