title: Pre-neoplastic lesion, mucin-depleted foci, reveals de novo high-grade             dysplasia in rat colon carcinogenesis.
abstract: Aberrant crypt foci (ACF) and mucin-depleted foci (MDF) have recently been             recognized as pre-neoplastic lesions in the colon of carcinogen-treated rodents.             In the present study, we analyzed the sequential development of ACF and MDF histopathologically             in the colon of rats from 5 to 40 weeks after DMH treatment. The numbers of ACF             per colon increased over time during the experiment, and were much higher than             the number in tumors, while the number of MDF per colon remained unchanged from             the early stage (the 5th week after carcinogen exposure), and approximate to those             in tumors. The incidence of ACF, which was much higher than that of tumors, also             increased gradually in a time-dependent manner. The incidence of MDF, however,             was similar to that of tumors and did not change significantly during the whole             experiment. No lesion as dysplasia with high-grade (DHG) or adenocarcinoma (AC)             were found in any large ACF from the 5th to 40th week histopathologically, whereas             all of the large MDF showed DHG or AC features. Even at 5 weeks, MDF showed features             of DHG. We classified these into two forms of MDF: flat and protruded MDF. At             40 weeks, the number of flat MDF per colon decreased significantly compared with             that at 20 weeks (p<0.05), however, the number of protruded MDF per colon increased             (p<0.01), and the percentage of DHG in a protruded MDF lesion decreased but             that of AC increased remarkably. In conclusion, MDF may develop into cancer through             the so-called 'de novo cancer' pathway.
authors.affiliation: Department of Pathology and Oncology, Graduate School of Medical Science, University of the Ryukyus, Okinawa, Japan. xu9659@mail.ryudai.jp
authors.forename: Changxu
authors.initials: C
authors.lastname: Cui
authors.forename: Reika
authors.initials: R
authors.lastname: Takamatsu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Doguchi
authors.forename: Akiko
authors.initials: A
authors.lastname: Matsuzaki
authors.forename: Masanao
authors.initials: M
authors.lastname: Saio
authors.forename: Naoki
authors.initials: N
authors.lastname: Yoshimi
mesh_terms: D058739:Aberrant Crypt Foci / Q000473:pathology*; D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000139:chemically induced / Q000473:pathology*; D015179:Colorectal Neoplasms / Q000473:pathology*; D004111:Dimenhydrinate; D008297:Male; D009077:Mucins / Q000032:analysis; D011230:Precancerous Conditions / Q000139:chemically induced / Q000473:pathology*; D051381:Rats; D011912:Rats, Inbred ACI
chemical_list: D009077:Mucins; D004111:Dimenhydrinate