ERBB4, one of the ErbB receptor tyrosine kinases, showed the functional coherence of 0.56, 0.59, 0.63, and 0.57 with APC, KRAS, PIK3CA, and TP53, respectively, which also participated in cancer associated functions such as MAPK cascade, cell migration and cell proliferation. The gene discussed is PIK3CA; the disease is cancer.