Detection of cancer clones in human gastric adenoma by increased DNA-instability and other biomarkers

Abstract

An immunohistochemical differential staining of cancerous cells with anti-cytidine antibody after denaturation of nuclear DNA by acid hydrolysis with 2N HCl at 30°C for 20 min (DNA-instability test) has been used as a marker of malignancy. The test was applied to bioptic tissues of human gastric polyp assessed histopathologically as foveolar hyperplastic polyp (13 cases), mild (58 cases), moderate (86 cases), and severe (20 cases) dysplasia, and adenocarcinomas (14 cases). The serial sections of the same tissues were also subjected to immunohistochemical staining for Ki67, p53, DNA-fragmentation factor (DFF45), and basic fibroblast growth factor (bFGF). The DNA-instability test was positive in 14 (100%) adenocarinoma cases, 20 (100%) severe dysplasia cases, 52 (60.5%) moderate dysplasia cases, and 12 (20.7%) mild dysplasia cases, indicating malignancy. All foveolar hyperplastic polyps were negative to the DNA-instability testing. Furthermore, the percentage of glands positive in the DNA-instability test steadily increased in going from mild (10%), to moderate (40%), to severe (100%) dysplasia, and adenocarcinoma (100%). All other biological markers tested in the present study showed significantly higher values in the adenoma glands, being positive to DNA-instability testing, irrespective of the dysplasia grade, as compared to those in the adenoma glands that were negative to DNA-instability testing. Furthermore, the former values were comparable to those in adenocarcinoma. These results indicate that cancer cell clones are already present at the adenoma stages showing a positive DNA-instability test, enhanced proliferative activity, p53 mutation, induction of DFF45 and bFGF. These factors allow cancer cell proliferation, producing heterogeneous subclones due to DNA-instability, enhancing their survival by escaping apoptosis, and providing abundant nutrients during the early-stage progression of gastric cancer. Based on these findings, we herein propose the concept of “procancer” (as opposed to “precancer”) as being a unique stage during the course of carcinogenesis and cancer progression. We designate the term to cancer clones at the very early stages of malignant progression that do not show distinguishable morphological atypia but do show positive DNA-instability testing and positive staining for various biomarkers such as Ki67, p53, DFF45, and bFGF. We also define the abnormal positive staining of these biomarkers, including the DNA-instability test as “functional atypia”, compared to the ordinary morphological atypia

MiR-145, a new regulator of the DNA Fragmentation Factor-45 (DFF45)-mediated apoptotic network

“…Induction of DFF45 seems to be involved in the production of heterogenous subclones in human gastric cancer cells, and in their enhanced ability to avoid apoptosis [35]. Hara et al found that when DFF45 is overexpressed in human renal cell carcinoma cells, it renders them highly resistant to therapy-induced apoptosis [36,37].…”

Comparative study of Western and Japanese criteria for biopsy-based diagnosis of gastric epithelial neoplasia

“…From a Western point of view, the final diagnosis rests on examination of the surgical or ESD specimen, because there is some possibility of cancer even if the diagnosis is LGD or HGD [21,23,36,[46][47][48]. Some studies have indicated that LGD and HGD should be treated, because genomic instability may already be present [49][50][51][52]. However, the European guidelines recommend reassessment with biopsy sampling and surveillance at 6-month to 1-year intervals for patients with HGD in the absence of endoscopically defined lesions [8].…”