TLR3 and pancreatic adenocarcinoma: Considering the changes of TLR3 expression levels in KIRC, LGG and PAAD, as well as the influence of TLR3 expression on the prognosis of these three cancers, and the close correlation between TLR3 and the tumor immune microenvironment, TLR3 may become a potential therapeutic target and an important molecular biomarker for judging the prognosis of KIRC, LGG and PAAD, as well as a diagnostic biomarker of KIRC, LGG and PAAD, especially an early diagnostic biomarker of KIRC.