PIK3CA and cancer: In addition to the demonstrated ability of OV to inhibit carcinogenesis in different cancer types by our group [8,9,10,22], the present study demonstrated that treatment with OV significantly suppressed the ability of CAL27 (2.91-fold, p < 0.001) and SCC-15 (2.67-fold, p < 0.001) cells to form tumorspheres (Figure 4A) with concomitant downregulation of PI3K, STAT3, TGFβ1, and β-catenin protein expression levels in OV-treated tumorspheres, compared to their control counterparts (Figure 4B).