Intratumoral genetic heterogeneity and progression of endometrioid type endometrial adenocarcinomas.
OBJECTIVE
Development of genetic heterogeneity is one mechanism whereby tumors may acquire increasing aggressiveness during neoplastic progression. In this study we relate development of intratumoral genetic heterogeneity to invasion and metastatic spread of sporadic endometrioid (type I) endometrial adenocarcinomas.


METHODS
Microsatellite unstable adenocarcinomas underwent detailed microsatellite allelotype mapping with reconstruction of neoplastic lineages using maximum parsimony analysis.


RESULTS
Within individual patients, tumor allelotypes sometimes varied between regions of histologically identical tumor, indicating that genotypic variation may reflect differences inapparent by histology. Comparison of noninvasive (surface/luminal) with invasive (myometrial invasion or metastasis) carcinoma showed highly related genotypes in 3/8 cases in which the invasive component can be recognized as evolved from the superficial tumor lineage by progressive clonal selection. In 3/8 cases superficial and invasive genotypes independently evolved different sets of altered microsatellites, indicating either divergence at an early stage in tumor evolution or independent selection events. A total of 2/8 cases had random patterns of marker distribution between sampled areas that were not informative in delineating systematic relationships between surface and invasive tumor.


CONCLUSIONS
We conclude from these results that endometrial tumor progression may occur through physical extension of existing clones or through creation of new subclones with altered growth properties. The latter occurs in about half of cases, where myometrial invasion may select for particular clones that are poorly represented on the luminal surface.
Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
W C
WC
Faquin
J T
JT
Fitzgerald
K A
KA
Boynton
G L
GL
Mutter
D000483:Alleles; D018269:Carcinoma, Endometrioid / Q000235:genetics* / Q000473:pathology*; D004273:DNA, Neoplasm / Q000032:analysis / Q000235:genetics; D018450:Disease Progression; D016889:Endometrial Neoplasms / Q000235:genetics* / Q000473:pathology*; D005260:Female; D018740:Genetic Heterogeneity; D005838:Genotype; D006801:Humans; D018895:Microsatellite Repeats / Q000235:genetics; D009361:Neoplasm Invasiveness; D010802:Phylogeny
D004273:DNA, Neoplasm