SERPINB3 and metastasis: PTK6 expression was associated with tumor grade in patients with early-stage cervical squamous cell cancer (P = 0.020); no significant association was detected between PTK6 expression level and age, tumor size, FIGO stage, deep cervical stromal invasion, pelvic lymph node metastasis, SCC antigen level, and lymphovascular space invasion (all P > 0.05) (Table 1).