Allelic loss analysis of early-stage flat-type colorectal tumors.
Ann Oncol
; 17(1): 43-9, 2006 Jan.
Article
in En
| MEDLINE
| ID: mdl-16249214
ABSTRACT
BACKGROUND:
Flat-type colorectal tumors are rare, but are known for their unusual flat morphology and aggressive clinical behavior despite their small size. To identify distinct genetic alterations, loss of heterozygosity (LOH) analysis was performed on microdissected tissues. MATERIALS ANDMETHODS:
DNA was extracted from multiple microdissected foci in 43 cases of early-stage flat-type colorectal tumors and LOH analysis was performed on 2q, 4q, 5q, 12q, 14q, 15q, 17p, 18q, 18p and 22q.RESULTS:
LOH patterns were detected in one of two forms (i) homogeneous LOH throughout the microdissected foci, which indicated the early acquisition of LOH; and (ii) heterogeneous LOH, which were detected in a part of analyzed foci. Homogeneous and heterogeneous LOH were most frequently detected on 17p (92%) followed by 18q (81%), 18p (81%), 5q (61%), 22q (51%), 14q (44%), 15q (41%), 2q (39%), 12q (36%) and 4q (32%). Homogeneous LOH was detected most frequently on 17p (68%) followed by 18p (53%), 18q (53%), 22q (34%) and 12q (27%). The average fractional allelic loss (FAL) for heterogeneous and homogeneous LOH was 0.57 and the average FAL for homogeneous LOH was 0.37.CONCLUSIONS:
Early flat-type colorectal tumors frequently shows the early occurrence of multiple LOH including 17p, 18p, 18q and 22q, which is coupled with additional LOH of other loci either simultaneously or in the early clonal progression phase. The extent and sequences of LOH may be the mechanisms responsible for the aggressive clinical behaviors of these tumors.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Precancerous Conditions
/
DNA, Neoplasm
/
Colorectal Neoplasms
/
Loss of Heterozygosity
Limits:
Adult
/
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Journal:
Ann Oncol
Journal subject:
NEOPLASIAS
Year:
2006
Document type:
Article
Affiliation country:
Japón