Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive form of pancreatic cancer. Its 5-year survival rate is only 3–5%. Perineural invasion (PNI) is a process of cancer cells invading the surrounding nerves and perineural spaces. It is considered to be associated with the poor prognosis of PDAC. About 90% of pancreatic cancer patients have PNI. The high incidence of PNI in pancreatic cancer limits radical resection and promotes local recurrence, which negatively affects life quality and survival time of the patients with pancreatic cancer.

To investigate the mechanism of PNI in pancreatic cancer, we analyzed the gene expression profiles of tumors and adjacent tissues from 50 PDAC patients which included 28 patients with perineural invasion and 22 patients without perineural invasion.

Using Monte-Carlo feature selection and Incremental Feature Selection (IFS) method, we identified 26 key features within which 15 features were from tumor tissues and 11 features were from adjacent tissues.

Our results suggested that not only the tumor tissue, but also the adjacent tissue, was informative for perineural invasion prediction. The SVM classifier based on these 26 key features can predict perineural invasion accurately, with a high accuracy of 0.94 evaluated with leave-one-out cross validation (LOOCV).

The in-depth biological analysis of key feature genes, such as TNFRSF14, XPO1, and ATF3, shed light on the understanding of perineural invasion in pancreatic ductal adenocarcinoma.

胰腺导管腺癌 (PDAC) 是最具侵袭性的胰腺癌。它的5年生存率只有3-5%。神经周围侵袭（PNI）是癌细胞侵入周围神经和神经周围空间的过程。它被认为与PDAC的不良预后有关。大约 90% 的胰腺癌患者患有 PNI。PNI在胰腺癌中的高发病率限制了根治性切除并促进了局部复发，这对胰腺癌患者的生活质量和生存时间产生了负面影响。

为了研究 PNI 在胰腺癌中的作用机制，我们分析了 50 名 PDAC 患者的肿瘤和邻近组织的基因表达谱，其中包括 28 名有神经周围侵犯的患者和 22 名没有神经周围侵犯的患者。

使用 Monte-Carlo 特征选择和增量特征选择 (IFS) 方法，我们确定了 26 个关键特征，其中 15 个特征来自肿瘤组织，11 个特征来自邻近组织。

我们的结果表明，不仅肿瘤组织，而且邻近组织，对于神经周围侵袭预测都有信息。基于这 26 个关键特征的 SVM 分类器可以准确预测神经周围侵袭，使用留一法交叉验证 (LOOCV) 评估的准确度高达 0.94。

对关键特征基因（如 TNFRSF14、XPO1 和 ATF3）的深入生物学分析有助于了解胰腺导管腺癌的神经周围浸润。