Qualitative DNA differences between two structurally different lesions: high-grade dysplasia and carcinoma in situ in colorectal adenomas.
BACKGROUND
Despite the fact that the Vienna classification of neoplasias in the gastrointestinal (GI) tract acknowledged low-grade dysplasia (LGD), high-grade dysplasia (HGD) and carcinoma in situ (CIS) and that most Western pathologists recognize CIS in many organs, both CIS and HGD are still used synonymously in colorectal adenomas. Differences between CIS and HGD in colorectal adenomas are reported.


METHODS
Five large colorectal adenomas (measuring >20 mm) having areas of both HGD and CIS were stained with hematoxylin and eosin (H&E) and with Feulgen stains.


RESULTS
The HGD areas showed tightly packed, spindle shaped, hyperchromatic cells with slight to moderate pleomorphic nuclei having coarse chromatin. In contrast, the CIS cells displayed marked pleomorphism, large vesicular nuclei and a prominent nucleolus. In H&E stain the hyperchromasia found in HGD nuclei was much less evident in CIS nuclei. The HGD nuclei were intensively stained (+++) with the DNA-specific Feulgen reaction but the CIS nuclei were not.


CONCLUSIONS
It would appear that following the completion of chromosomal mutations in the nuclei of HGD-cells, their DNA, carrying the new genetic information, is transcribed into RNA in the nuclei of CIS. Thus, through messenger-RNA, the production of mutated cytoplasmic proteins, required for the ultimate invasion of the lamina propria mucosa (and beyond), would be triggered.
Rubio
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Gastrointestinal and Liver Pathology Research Laboratory, Department of Pathology, Karolinska Institute and University Hospital, 17176, Stockholm, Sweden. Carlos.Rubio@ki.se
D000236:Adenoma / Q000235:genetics* / Q000473:pathology; D002278:Carcinoma in Situ / Q000235:genetics* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D004273:DNA, Neoplasm / Q000032:analysis*; D006801:Humans; D012394:Rosaniline Dyes; D013194:Staining and Labeling / Q000379:methods
D004273:DNA, Neoplasm; C007722:Feulgen stain; D012394:Rosaniline Dyes