Preoperative plasma IGFBP2 is associated with nodal metastasis in patients with penile squamous cell carcinoma

The nodal status is a strong predictor for clinical outcome in patients with penile cancer. We aimed to evaluate the association between preoperative plasma IGFBP2 levels and nodal status in patients with penile squamous cell carcinoma (PSCC).

This retrospective study enrolled 56 penile cancer patients who underwent penectomy between 2015 and 2017. Preoperative plasma IGFBP2 levels were detected by enzyme linked immunosorbent assay, which was analyzed in association with clinicopathological parameters (age, body mass index, pathological grade, phimosis, histological subtype, tumor stage, and nodal status). Univariable and Multivariable Cox regression analysis was conducted to identify the prognostic factors that influence disease free survival in PSCC. CCK8 assay and clonogenic assay were used to evaluate the cell viability and tumorigenic potential of PSCC cell line, respectively; wound healing assay, and transwell invasion assay were conducted to evaluate the effect of IGFBP2 depletion on cell migration and invasion in PSCC cells; IGFBP2 protein expression was analyzed by Western blotting.

Plasma IGFBP2 levels were markedly higher in preoperative PSCC than those in healthy male subjects (P = 0.0007). Penectomy led to a significant reduction of plasma IGFBP2 levels in PSCC patients (P = 0.0098). Preoperative plasma IGFBP2 levels were significantly associated with nodal status of PSCC (P < 0.0001). At the cutoff value of 486.2 ng/ml, preoperative plasma IGFBP2 produced a sensitivity of 80.8% and a specificity of 86.7% to discriminate nodal metastasis. Preoperative plasma IGFBP2 levels could serve as independent prognostic factor for disease free survival in PSCC (P = 0.001). Further, knockdown of IGFBP2 expression suppressed cell growth, inhibited clonogenesis, and attenuated cell migration and invasion in Penl1 cells; depletion of IGFBP2 expression attenuated the levels of p-AKT and p-ERK1/2, while increased the expression of p16 and cleaved caspase-3 in Penl1 cells. Silencing IGFBP2 also led to a considerable decline of MMP2/9 levels in culture supernatant of Penl1 cells.

Higher preoperative plasma IGFBP2 was closely associated with nodal metastasis, which might serve as a useful diagnostic and prognostic biomarker for clinical management of PSCC. IGFBP2 might play an important role in the malignant progression of PSCC. Therapeutic strategies targeting IGFBP2-related signaling pathways may have a therapeutic benefit in PSCC patients.