PTK7 and neoplasm: The MTT-based cellular proliferation assay for the knockdown (siPTK7) and the control cells (siControl) suggested that the growth of siPTK7 was significantly slower than siControl (p < 0.01 for TE-5 and p < 0.05 for TE-9), indicating a promoting role of PTK7 in tumor cell proliferation (Fig. 2a, b).Supporting this notion, overexpression of PTK7 in both cell lines significantly promoted cell growth (Fig. 2c, d).