Abstract | OBJECTIVE: Serial colonoscopic observations were prospectively conducted to elucidate the natural history of nonpolypoid tumors. Furthermore, to clarify whether cell kinetic status affects the tumor development, proliferative indices, apoptotic indices, and K-ras codon 12 point mutations on biopsy specimens were investigated. METHODS: Seventy-five colorectal tumors, 13 polypoid and 62 nonpolypoid type (56 flat elevated and six depressed type) were studied. Proliferating and apoptotic cells were detected with anti-Ki-67 antibody and the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling method, respectively. Point mutations at K-ras codon 12 were examined by enriched polymerase chain reaction-based restriction fragment length polymorphism assay. RESULTS: The average follow-up period was 22 months (range 1-50). The lesions of subsequent exophytic growth, unchanged shape, depressed growth, and disappearance were observed in 0%, 92%, 0%, and 8% of polypoid type, in 39%, 39%, 13%, and 9% of flat elevated type, and in 33%, 67%, 0%, and 0% of depressed type, respectively. There was no significant difference in tumor size between initial and follow-up colonoscopy. Nonpolypoid tumors apparently changed to the exophytic growth during 2 yr or more. The tumors with exophytic growth had significantly higher proliferative indices/apoptotic indices ratios than those with unchanged morphology and disappearance/depressed growth (p < 0.05, respectively). K-ras codon 12 point mutations did not correlate with tumor development. CONCLUSIONS: Cell kinetic status plays an important role in determining minute colorectal tumor development, but not K-ras codon 12 mutations. Minute nonpolypoid adenomas frequently tend to grow slowly, and nearly 40% of those become the exophytic growth with time. Most of minute nonpolypoid tumors seem to follow the adenoma- carcinoma sequence.
|
Authors | Jiro Watari, Yusuke Saitoh, Takeshi Obara, Mikihiro Fujiya, Atsuo Maemoto, Tokiyoshi Ayabe, Toshifumi Ashida, Kinichi Yokota, Yutaka Orii, Yutaka Kohgo |
Journal | The American journal of gastroenterology
(Am J Gastroenterol)
Vol. 97
Issue 8
Pg. 2109-15
(Aug 2002)
ISSN: 0002-9270 [Print] United States |
PMID | 12190185
(Publication Type: Journal Article)
|
Chemical References |
|
Topics |
- Adenoma
(genetics, pathology)
- Adult
- Aged
- Aged, 80 and over
- Codon
- Colonoscopy
- Colorectal Neoplasms
(genetics, pathology)
- Female
- Genes, ras
(genetics)
- Humans
- Male
- Middle Aged
- Point Mutation
- Polymorphism, Restriction Fragment Length
- Prospective Studies
|