Pancreatic ductal adenocarcinoma (PDAC) is still a difficult malignant tumor to treat and is only associated with a survival time of a few months even under current chemotherapy protocols.
A promising therapeutic option in the treatment of solid malignant neoplasms is immunotherapy, although a clinical benefit for single-agent immunotherapy for PDAC has not yet been proven. Reasons could be complex immunosuppressive mechanisms within the tumor, influenced by the tumor microenvironment. Studies on surgical specimens have shown that tumor-associated cluster of differentiation 68 (CD68)-positive M1 macrophages, cluster of differentiation 163 (CD163)-positive M2 macrophages and forkhead-box-protein P3 (FOXP3)- as well as cytotoxic T-lymphocyte-associated protein 4 (CTLA4)-positive regulatory T-cells (Treg) have a prognostic relevance.
This work examined whether risk stratification of PDAC using immunohistochemical examination of CD68, CD163, FOXP3 and CTLA4 is already possible with material obtained by endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNA). This would allow more precise statements about the prognosis to be made pretherapeutically/preoperatively at the time of diagnosis or to choose a targeted immunotherapy without the need for further, possibly invasive sample collection.
Comparable to the results obtained in the literature using surgical specimens, there was a prolonged survival time/lower hazard ratio with high antibody expression for the antibody against CD68, while high antibody expression was associated with a shortened survival time/higher hazard ratio for CD163, FOXP3 and CTLA4. The results were not significant (p-value > 0.05). Because of the small number of cases (n=58) and the limitations of the often-sparse material no significant results could be achieved.
Considering the encouraging Hazard ratio the presented work has shown further studies with higher case numbers seem sensible, especially in view of the increasing importance of personalized immunotherapy in tumor diseases and the still poor prognosis of PDAC to be able to provide the patient with improved or more targeted therapy.