The presence of intratumoral Porphyromonas gingivalis correlates with a previously defined pancreatic adenocarcinoma, immune cell expression phenotype and with tumor resident, adaptive immune receptor features.

The association between pancreatic adenocarcinoma (PAAD) and the pancreatic microbiome is not fully understood, although bacteria may decrease the effectiveness of chemotherapy and lead to anti-apoptotic, pro-inflammatory-microenvironments. To better understand the relationship between the PAAD microbiome and the microenvironment, we identified Porphyromonas gingivalis-positive PAAD samples and found a strong association between intratumoral Porphyromonas gingivalis and: (a) an immune cell gene expression phenotype previously defined by others as gene program 7; and (b) recovery of immunoglobulin recombination, sequencing reads. We applied a novel chemical complementarity scoring algorithm, suitable for a big data setting, and determined that the previously established, Porphyromonas gingivalis antigen, rpgB had a reduced chemical complementarity with T-cell receptor (TCR) complementarity-determining region-3 amino acid sequences recovered from PAAD samples with Porphyromonas gingivalis in comparison to TCR-rpgB chemical complementarity represented by the PAAD samples that lacked Porphyromonas gingivalis. This finding strengthens the existing body of evidence correlating Pophyromonas gingivalis with PAAD, which may have implications for treatment and prognosis of patients. Furthermore, demonstrating the correlation of Pophryomonas gingivalis and gene program 7 raises the question of whether Pophryomonas gingivalis infection is responsible for the gene program 7 subdivision of PAAD?