A Novel Role of Interleukin 13 Receptor alpha2 in Perineural Invasion and its Association with Poor Prognosis of Patients with Pancreatic Ductal Adenocarcinoma

Perineural invasion (PNI) is one of the major pathological characteristics of pancreatic ductal adeno-carcinoma (PDAC), which is mediated by invading cancer cells into nerve cells. Herein, we identify the overexpression of Interleukin-13 Receptor alpha2 (IL-13R alpha 2) in the PNI from 236 PDAC samples by studying its expression at the protein levels by immunohistochemistry (IHC) and the RNA level by in situ hybridization (ISH). We observe that >= 75% samples overexpressed IL-13R alpha 2 by IHC and ISH in grade 2 and 3 tumors, while >= 64% stage II and III tumors overexpressed IL-13R alpha 2 (>= 2+). Interestingly, >= 36 % peripancreatic neural plexus (PL) and >= 70% nerve endings (Ne) among PNI in PDAC samples showed higher levels of IL-13R alpha 2 (>= 2+). IL-13R alpha 2 +ve PL and Ne subjects survived significantly less than IL-13R alpha 2 -ve subjects, suggesting that IL-13R alpha 2 may have a unique role as a biomarker of PNI-aggressiveness. Importantly, IL-13R alpha 2 may be a therapeutic target for intervention, which might not only prolong patient survival but also help alleviate pain attributed to perineural invasion. Our study uncovers a novel role of IL-13R alpha 2 in PNI as a key factor of the disease severity, thus revealing a therapeutically targetable option for PDAC and to facilitate PNI-associated pain management.