Pancreatic cancer associated fibroblasts display normal allelotypes

Abstract

Background: Recent studies have reported widespread copy number alterations and p53 mutations arising in cancer associated stromal cells. The aim of this study was to determine if pancreatic cancer associated fibroblasts display similar genetic alterations.

Design: Cancer-associated fibroblast cultures were established from 7 primary pancreatic adenocarcinomas. These fibroblasts and corresponding normal tissues when available were analyzed for genome-wide copy number changes using Affymetrix 250K SNP microarrays. Evidence of p53 protein expression, an indicator of p53 mutation was determined by immunohistochemical labeling of tissue microarrays containing 117 pancreatic ductal adenocarcinomas.

Results: Pancreatic cancer associated fibroblasts did not show any evidence of somatic copy number gains or losses. p53 protein expression was confined to invasive pancreatic adenocarcinoma cells and was not expressed in cancer-associated fibroblasts.

Conclusions: We find no evidence that pancreatic cancer associated fibroblasts harbor somatic copy number changes or immunohistochemical evidence of p53 mutations.

Figure 1

Copy number analysis of four cancer associated fibroblast cultures and matching normal genomis DNA hybridized o SNP arrays. No copy number gains or losses were predicted by Hidden Markov’s model.

Figure 2

Copy number gains (red) and losses (blue) in pancreatic cancer cell lines ASPc1 and Panc1 relative to the 270 HapMap data collection. For each chromosome, ASPc1 is represented in the top panel and Panc1 is represented in the bottom panel.

Figure 3

Representative heat map of copy number values (top panel) and plot of genotype calls (bottom panel) on chromosomes 1, 2, amd 3 for one CAF sample relative to its match normal DNA. The heat map plots copy number at each SNP. The paired row of genotype calls represents one CAF and its match normal DNA

Figure 4

Localizatin of p53 protien in ductal adenocarcinomaof the pancreas. (A) Hematoxylin and eosin staining demonstrates scattered malignant epithelial glands (arrows) and surrounding stromal fibroblasts and infiltration of inflammatory cells. (B) *-SMA expressiom is observed in stromal fibroblasts and (C) expression of cytoplasmic cytokeratin 19 is exclusively observed in malignant epithelial cells. (D) Immunohistochemical staining of p53 protien show overexpression in the malignant neoplastic epithelial cells with no detectable expression in the surrounding stromal fibroblasts.