FIGURE S1. The effect of FRMD6 silencing on the proliferation of thyroid cancer cells. TPC-1 and K1 cells were transfected with FRMD6 siRNA or NC siRNA and cultured for 48 h. (A) The downregulation of FRMD6 in siRNA-transfected cells was verified via western blotting. The effects of FRMD6 silencing on thyroid cancer cell proliferation were evaluated via (B, C) CCK-8 assay and (D, E) EdU assay. *p < 0.05 and **p < 0.01

FIGURE S2. The effect of FRMD6 silencing on the invasion of thyroid cancer cells. (A, B) The invasive ability of thyroid cancer cells transfected with FRMD6 siRNA was measured via transwell assay (**p < 0.01). (C) The effect of FRMD6 silencing on the levels of E-cadherin, vimentin, and N-cadherin was detected by western blotting

FIGURE S3. The effect of FRMD6 silencing on YAP1 activation in thyroid cancer cells. (A) The effect of FRMD6 silencing on the levels of phospho-MST1, LATS1, and YAP1 was measured via western blotting assay. (B) The effect of FRMD6 silencing on the nuclear translocation of YAP1 was assessed via immunofluorescence assay. (C) The effect of FRMD6 silencing on YAP1 activation was monitored via luciferase reporter gene assay (**p < 0.01)

FIGURE S4. FRMD6 inhibition reversed FRMD6-overexpression-induced suppression of YAP1. (A) TPC-1 and K1 cells were cotransfected with FRMD6 vector and FRMD6 siRNA for 48 h, and levels of FRMD6, and phospho-MST1, LATS1, and YAP1 were measured via western blotting. (B) YAP1 transcriptional activity was monitored via luciferase reporter gene assay (**p < 0.01)