Polo‐Like Kinase 1 Expression in Colorectal Cancer: Association With <scp>RAS</scp> Mutations

Polo-like kinase 1 (PLK1) controls mitotic spindle formation and cytokinesis. However, its role as a predictive biomarker for treatment outcomes in colorectal cancer (CRC) remains underexplored, particularly in the context of RAS mutations. We retrospectively analyzed the relationships among PLK1 expression, clinicopathological factors, and survival in 225 patients who underwent CRC surgery. We also analyzed the relationship between PLK1 expression and survival after adjuvant chemotherapy and how RAS mutation influenced the prognosis. We found that PLK1 expression was significantly correlated with histopathology (p < 0.0001) and perineural invasion (p = 0.005). The high PLK1 expression group tended to have a worse prognosis in terms of relapse-free survival than the low expression group for all patients (p = 0.060) and patients with stage III disease (p = 0.055). In patients who received adjuvant chemotherapy for stage III CRC, high PLK1 expression was the only poor prognostic factor for relapse-free survival (p = 0.01), and those with mutated RAS had a significantly poorer prognosis than those with wild-type RAS (p = 0.027). In patients with CRC, high PLK1 expression was associated with poor survival after adjuvant chemotherapy, and there was potential involvement of the RAS mutation.