ObjectivePancreatic cancer has a poor prognosis due to its high malignancy and rapid progression. The limited immunogenicity of pancreatic cancer (PAAD) contributes to its low responsiveness to immunotherapy, yet its underlying mechanism remains poorly understood. As a cancer promoting gene, Twist participates in EMT in various tumors and promotes tumor progression. The interplay between EMT and the tumor microenvironment (TME) emerges as a pivotal factor influencing tumor immunity and response to immunotherapy. Twist therefore has potential as a biomarker for gauging the outcome of tumour immunotherapy.This research aimed to assess the Twist's prognostic significance in PAAD and its relationship to immunotherapy response.MethodsIn this research, transcriptional data and epigenetic alterations of Twist in pancreatic cancer, along with their impact on the prognosis of PAAD patients, were analyzed using databases. Functional enrichment analysis elucidated the biological role of Twist in PAAD. Subsequently, databases including CIBERSORT and TIDE were employed to investigate the association between Twist expression and immune cell infiltration, immune checkpoint genes, and immunotherapy sensitivity within the pancreatic cancer immune microenvironment.Paraffinized specimens from patients with pancreatic ductal adenocarcinoma confirmed by postoperative pathology were selected for Twist expression verification, and the difference was analyzed by Chi-square test; uncontaminated pancreatic cancer cell lines were used for Twist expression verification, and the differences were analyzed by Student t-test.ResultsTwist mRNA expression was notably upregulated in PAAD, positively correlating with gene methylation levels. Analyses of Kaplan–Meier and Cox regression showed a correlation between better overall survival and lower Twist expression. Functional annotation indicated that Twist-associated differentially expressed genes (DEGs) were involved in EMT regulation and acute inflammation. High expression of Twist leads to a significant reduction in the infiltration of anti-tumor immune cells such as Monocytes, NKcellsactivated, and TcellsCD8, further supporting its creation of a typical immunosuppressive microenvironment in pancreatic cancer. Twist expression is positively correlated with the expression of HARVCR2, LAIR1, LGALS3 and other genes, which may be related to the treatment response to immune checkpoint inhibitors (ICIs). TIDE analysis predicts that patients with high expression of Twist will be insensitive to immunotherapy. Twist is significantly over-expressed in pancreatic cancer cell lines and tissues, and is negatively correlated with E-cadhrin expression, but positively correlated with N-cadherin,Snail, and ZEB1.ConclusionHigh Twist expression in PAAD signifies a grim prognosis. Its elevated levels not only contribute to tumor progression through EMT induction but also exert regulatory control over the immune microenvironment, leading to immunosuppression and diminished effectiveness of immunotherapy.