Gene expression profiling of morphologic subtypes of pancreatic ductal adenocarcinoma using surgical and EUS-FNB specimens

Pancreatology. 2021 Apr;21(3):530-543. doi: 10.1016/j.pan.2021.01.025. Epub 2021 Feb 9.


Background/objectives: Various classifications of pancreatic ductal adenocarcinoma (PDAC) based on RNA profiling resulted in two main subtypes. Kalimuthu and coworkers proposed a morphology-based classification that concurred with these subtypes. Immune therapy approaches in PDAC were so far disappointing. Morphologic PDAC subtypes may differ regarding key immune-oncology pathways. We aimed to examine the reproducibility and prognostic value of Kalimuthu's morphologic classification, and to evaluate differences between subtypes regarding gene expression related to tumor biology and immune-oncology.

Methods: PDAC specimens from 196 patients were included, 108 consecutive chemotherapy-naïve surgical specimens and 88 endoscopic ultrasound-guided fine needle biopsies (EUS-FNBs). The specimens were evaluated as per Kalimuthu by two pancreatic pathologists, resulting in Group A and Group B tumors. Digital mRNA expression profiling was performed, on the surgical specimens using the NanoString IO360 panel of 770 key tumor biology related and 30 custom-genes, and on the EUS-FNBs using a targeted panel of 123 genes.

Results: Morphologic subtyping reached substantial interobserver agreement between the two pathologists. In the surgical and EUS-FNB cohorts, 44.4% and 38.6% were Group A tumors, which were associated with improved survival. Group A showed higher expression of immune-related genes and cytokine/chemokine/interleukin signaling and Group B of genes related to cancer cell proliferation and cell cycle regulation. Hierarchical clustering based on significant differences in gene expression levels between Groups A and B revealed clusters with prognostic value.

Conclusions: Morphologic subtyping according to Kalimuthu is reproducible and holds prognostic value, in surgical as well as EUS-FNB specimens. As upregulation of immune-related genes was found in Group A, future studies should evaluate the potential of immune therapy approaches with special emphasis on this subtype of PDAC.

Keywords: Differentiation grading; Gene expression analysis; Immunohistochemistry; Pancreatic cancer; Subtyping.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / genetics*
  • Carcinoma, Pancreatic Ductal / classification
  • Carcinoma, Pancreatic Ductal / genetics*
  • Carcinoma, Pancreatic Ductal / pathology
  • Carcinoma, Pancreatic Ductal / surgery
  • Endoscopic Ultrasound-Guided Fine Needle Aspiration
  • Female
  • Gene Expression Profiling*
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Grading
  • Observer Variation
  • Pancreatic Neoplasms / classification
  • Pancreatic Neoplasms / genetics*
  • Pancreatic Neoplasms / pathology
  • Pancreatic Neoplasms / surgery
  • Prognosis
  • Reproducibility of Results
  • Transcriptome*


  • Biomarkers, Tumor