Re-evaluation of the relationship between PrPc expression and patient prognosis in primary esophageal squamous cell carcinoma and primary hepatocellular carcinoma.

PrPc is expressed in various tumors and is associated with cancer progression, but previous studies have shown conflicting results regarding its relationship with patient prognosis-potentially due to differences in the antibodies used. This study aimed to clarify the relationship between PrPc expression and primary esophageal squamous cell carcinoma (ESCC) and primary hepatocellular carcinoma (HCC) using a novel anti-PrPc antibody, 4AA-m, noted for its high specificity and sensitivity. We used flow cytometry to detect PrPc expression in ESCC and HCC cell lines. Immunohistochemistry with 4AA-m was then performed on tissue microarrays from 179 patients with primary ESCC and 92 patients with primary HCC. PrPc expression was semi-quantitatively assessed using the Tumor-DAB-H-Score, and its association with tumor prognosis was analyzed. In ESCC, PrPc expression was negatively correlated with lymph node metastasis, and patients with high PrPc expression had better overall survival compared to those with low expression. PrPc expression was identified as an independent prognostic factor for overall survival in ESCC. In HCC, patients with positive PrPc expression had shorter recurrence-free survival (RFS) than those without PrPc expression. PrPc expression was also found to be an independent prognostic factor for RFS in HCC.