Cytogenetic changes are widely unknown for nonpolypoid (synonymously termed as "flat" or "depressed") @entity2513 . A comparison with polypoid @entity652 will contribute to the discussion whether different genetic pathways for colorectal tumorigenesis depending on its origin from nonpolypoid or polypoid @entity652 exist. Tissue samples of nonpolypoid (n = 22), polypoid (n = 28) @entity652 , @entity189 ex-nonpolypoid @entity652 (n = 9), @entity189 ex-polypoid @entity652 (n = 14), and normal colonic mucosa (n = 9) were investigated by comparative genomic hybridization of whole genomic DNA. Chromosomal imbalances were detected from average comparative genomic hybridization profiles for each entity. Nonpolypoid @entity652 show recurrent chromosomal losses on chromosomes 16, 17p, 18, 20, and 22 and gains on chromosomes 2q, 4q, 5, 6, 8q, 12q, and 13q. In polypoid @entity652 losses of whole chromosomes 16, 18, and 22 and gains of chromosomes 7q and 13 were detected. The frequency of copy number changes was higher in nonpolypoid compared to polypoid @entity652 and early onset of chromosomal changes became apparent in low-grade @entity1141 of nonpolypoid @entity652 . Gains on chromosomes 2q, 5, 6, 8q, and 12q and losses on chromosomes 17p and 20 occurred exclusively in nonpolypoid @entity652 , whereas 16p deletions are significantly more frequent in nonpolypoid than in polypoid @entity652 . @entity189 ex-nonpolypoid @entity652 are characterized by more complex aberration patterns compared to nonpolypoid @entity652 exhibiting frequent losses on chromosomes 8p, 12q, 14, 15q, 16, 17p, 18, and 22 and gains on 3q, 5, 6, 7, 8q, 12q, and 13, respectively. Normal colonic mucosa showed no chromosomal imbalances. Distinct differences of chromosomal imbalances between nonpolypoid and polypoid @entity2513 have been characterized that support the hypothesis that different genetic pathways may exist in the development of @entity2513 exhibiting nonpolypoid and polypoid phenotype.

Distinct chromosomal imbalances in nonpolypoid and polypoid XXXX indicate different genetic pathways in the development of colorectal neoplasms.

@entity652 :: ('MESH:D000236', 'Disease') :: ['adenomas'] @entity2513 :: ('MESH:C563365', 'Disease') :: ['colorectal adenomas'] @entity189 :: ('MESH:D002277', 'Disease') :: ['carcinomas', 'Carcinomas'] @entity1141 :: ('MESH:C535662', 'Disease') :: ['dysplasias']
@entity2513 :: (MESH:C563365,Disease) :: ['colorectal adenomas']
