PLCG1 and squamous cell carcinoma: PLCG1 has emerged as a possible driver for cell proliferation, and increased expression levels of PLCG1 have been observed in breast cancer, colon cancer, and squamous cell carcinoma (Arteaga et al., 1991; Noh et al., 1994; Park et al., 1994; Xie et al., 2010).