Pancreatic ductal adenocarcinoma (PDAC) has a suboptimal response to standard therapies that modestly impact survival due to its ability to evade host immune surveillance. Emerging evidence has shown that the co-inhibitory receptors, such as programmed death 1 (PD-1), play a critical role in cancer immune-editing. Programmed death-ligand 1 (PD-L1) is an immune checkpoint that is often activated in cancer and plays a pivotal role in the initiation and progression of cancer. The advent of immunotherapy, with checkpoint inhibitors, which block PD-L1 interaction between tumor cells and activated T cells, has significantly altered the treatment algorithm for several solid tumors. However, the clinicopathologic significance and prognostic value of PD-L1 in PDAC remains controversial. The main technical ground may be that PDAC PD-L1 expression quantification is limited to surgical resection specimens and dependent on specific immunohistochemistry (IHC) tests. In addition, PD-L1 expression has not been extensively assessed before surgery in treatment-naive PDAC patients, due to the current IHC test requirement for a histologic rather than a cytologic evaluation. However, a recent study showed that EUS-fine needle biopsy (FNB) can successfully determine primary pancreas malignancy PD-L1 status. One recently identified subtype within the genomic landscape of PDAC is the mismatch repair-deficient (dMMR) tumor. Evaluation of dMMR status is particularly important following the FDA approval of the PD-1 inhibitor, pembrolizumab, for the treatment of unresectable or metastatic, microsatellite instability-high (MSI-H) or dMMR PDAC that have progressed following prior treatment, and have no satisfactory alternative treatment options. The objectives of the project will include the assessment of tumor PD-L1/dMMR expression in patients with PDAC using EUS-FNB samples and the prospective correlation of MMR status and PD-L1 expression with overall survival and progression-free survival of PDAC patients.
Study Type
OBSERVATIONAL
Enrollment
30
EUS WITH EUS-FNB will be performed for confirmation of diagnosis and analysis of MMR status and PD-L1 expression Protocol of EUS with EUS-FNB should include linear EUS instruments with complete examinations of the pancreas. Tumor characteristics (echogenicity, echostructure, size) will be described as well as presence/absence of power Doppler signals. EUS-FNB will be performed in all pancreatic masses with at least three passes in the absence of an onsite cytopathologist using a fanning technique with a 22-gauge needle (SharkCore FNB needle Medtronic Corp. or Acquire FNB needle Boston, MA).
IHC will be performed on treatment-naïve formalin-fixed paraffin-embedded EUS-FNB pancreatic specimens. Briefly, 4-μm-thick tissue sections will be stained using the Ventana BenchMark XT automated slide-staining system using the following antibodies: Anti-PD-L1 (clone SP263, VENTANA, Tucson, AZ), MLH1 (clone G168-728, Cell Marque, Rocklin, California, United States), MSH2 (clone FE11, Biocare Medical, Concord, Massachusetts, United States), MSH6 (clone BC/44, Biocare Medical, Concord, Massachusetts, United States), and PMS2 (clone A16-4, Biocare Medical, Concord, M Massachusetts, United States). Antigen-antibody reactions will be visualized using UltraView detection with diaminobenzidine as the chromogen. The specimen will be considered to have PD-L1 expression if PD-L1 is expressed in ≥ 1 % of tumor cells and a high level of expression if ≥ 50 %. Tumors will be classified as dMMR if they exhibit absent nuclear staining of DNA mismatch repair proteins (MLH1, MSH2, MSH6, or PMS2).
Feasibility of PD-L1 expression analysis on EUS-FNB pancreatic specimens
the percentage of cases where EUS-FNB material was adequate to determine PDL-1 expression
Time frame: 1 year
Feasibility of MMR status analysis on EUS-FNB pancreatic specimens
the percentage of cases where EUS-FNB material was adequate to determine MMR status
Time frame: 1 year
Tumor response
Tumor response will be assessed according to the Response Evaluation Criteria in Solid Tumors (RECIST). According to RECIST guidelines,complete response (CR) is defined as the complete disappearance of the tumor, partial response (PR) as ≥30% decrease in longest diameter (LD), progressive disease (PD) as ≥20% increase in LD, and stable disease (SD) as a decrease or increase less than PR or PD based on anatomic assessment. Patients with CR or PR will be defined as responders, whereas those with PD or SD are defined as non-responders.
Time frame: 3 months
Overall survival
The overall survival will be measured from the day of diagnosis to the date of death
Time frame: up to 12 months
Progression-free survival
The progression-free survival (PFS) will be measured from the day of diagnosis to the date of progressive disease.
Time frame: up to 12 months
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