PIBF1 expression and survival outcome in TNBC and Non-TNBC breast cancer patients with lymph node metastasis who undertaken chemotherapy.

Progesterone-induced blocking factor 1 (PIBF1) is linked to pregnancy-induced immunity and tumor evasion of maternal immunity. PIBF1 is overexpressed in several cancers, including breast, cervical, and lymphoma. However, limited research is available on the role of PIBF1 in breast cancer and its clinical outcomes. Therefore, we investigated the relationship between PIBF1 expression, prognosis, and its impact on chemotherapy response. Samples from 231 patients with high-risk triple-negative breast cancer (TNBC) who underwent surgery between 2008 and 2013 with lymph node metastasis and underwent taxane-based adjuvant chemotherapy were collected. Additionally, 238 non-TNBC patients matched to TNBC patients were selected. Immunohistochemical detection of the PIBF1 protein in tissues was conducted using a cut-off value of 3 (intensity plus proportion). Kaplan-Meier survival analysis assessed the probability of overall survival (OS). Using the clonogenic unit assay and knockdown methodologies in breast cancer cell lines, we examined the correlation between PIF1 expression and chemosensitivity. In a study of 469 patients with breast cancer, non-TNBC (n = 238) and TNBC (n = 231), those with PIBF1 expression manifested a lower histologic grade (p < 0.001), reduced p53 (p < 0.001) and decreased Ki-67 (p < 0.001) compared with their non-expressing counterparts. A significant difference in OS for patients with PIBF1 was observed, with non-TNBC patients showing superior outcomes. PIBF1 expression showed a relation with a better prognosis, and the statistical significance was borderline (hazard ratio = 0.44, 95% confidence interval = 0.18-1.11, p = 0.082). A correlation between PIBF1 expression in breast cancer cell lines (BT549, HCC70, BT20, and HS578T) and their sensitivity to paclitaxel was shown in vitro, with certain cell lines showing significant viability reductions and also resisting the treatment after PIBF1 knockdown. We observed a correlation between PIBF1 expression and improved prognosis in breast cancer patients with nodal metastasis undergo taxane-based chemotherapy, particularly in the non-TNBC cohort. We discerned a relationship between PIBF1 and chemosensitivity in our in vitro studies. These findings suggest the potential usefulness of PIBF1 as a predictive marker for guiding therapeutic approaches.