Intratumor genetic heterogeneity in advanced human colorectal adenocarcinoma

Colorectal carcinogenesis is widely accepted as one of the best‐characterized examples of stepwise progression. The existing colorectal carcinogenesis model assumes genetic homogeneity of individual tumors for the main known genetic alterations: K‐ras and p53 genes point mutations and loss of heterozygosity (LOH) of chromosome 5q and 18q. The object of the present study was to demonstrate the existence of an intratumor genetic heterogeneity in advanced sporadic colorectal carcinoma for these genetic alterations. Using improved tissue microdissection and DNA extraction, for each tumor, amplifiable DNA was obtained from 15 to 20 areas, of which 1 to 2 concerned lymph node metastases (LNM). This study revealed that 10 of 15 (67%) analyzed tumors were heterogeneous for at least 1 genetic alteration, with between 2 and 6 genotypically different clones detected per tumor. No correlation was observed between the genotype of these subclones and histological differentiation or invasive propensity. Intratumor heterogeneity was more frequently observed for LOH than for point mutations, 67% and 58% for LOH at APC and DCC locus, and 20% for mutation of either the K‐ras or p53 gene. In 5 of the 9 (56%) heterogeneous cases with available LNM, the genotype observed in the LNM was different from that of the main clone in the primary tumor, and moreover, 2 of the LNM displayed a genotype undetected in the primary tumor. In conclusion, intratumor genetic heterogeneity was demonstrated in advanced sporadic colorectal carcinoma and was represented as topographically distinct genotypic subclones. Taking into account such a significant genetic heterogeneity of colorectal tumors, the use of genetic markers for prognosis management should be reconsidered. © 2001 Wiley‐Liss, Inc.

[1]  O. Dodge.  Histological Typing of Intestinal Tumours , 1977, British Journal of Cancer.

[2]  P. Quirke,et al.  Heterogeneity of colorectal adenocarcinomas evaluated by flow cytometry and histopathology. , 1985, British Journal of Cancer.

[3]  J. Arends,et al.  Comparison of phenotypic and genotypic features in human primary large bowel carcinomas and lymph node metastases. , 1987, Cancer research.

[4]  B. Vogelstein,et al.  Prevalence of ras gene mutations in human colorectal cancers , 1987, Nature.

[5]  Y. Nakamura,et al.  Allelotype of colorectal carcinomas. , 1989, Science.

[6]  D. Ledbetter,et al.  Chromosome 17 deletions and p53 gene mutations in colorectal carcinomas. , 1989, Science.

[7]  B. Vogelstein,et al.  A genetic model for colorectal tumorigenesis , 1990, Cell.

[8]  Kathleen R. Cho,et al.  Identification of a chromosome 18q gene that is altered in colorectal cancers. , 1990, Science.

[9]  S. Altschul,et al.  Identification of FAP locus genes from chromosome 5q21. , 1991, Science.

[10]  B. Brismar,et al.  Colorectal carcinoma. DNA ploidy pattern and prognosis with reference to tumor DNA heterogeneity. , 1992, Analytical and quantitative cytology and histology.

[11]  H. Rabes,et al.  K‐ras point mutations in human colorectal carcinomas: Relation to aneuploidy and metastasis , 1992, International journal of cancer.

[12]  D. Schaid,et al.  Current status of adjuvant chemotherapy for colorectal cancer: Can molecular markers play a role in predicting prognosis? , 1992 .

[13]  D. Schaid,et al.  Current status of adjuvant chemotherapy for colorectal cancer. Can molecular markers play a role in predicting prognosis? , 1992, Cancer.

[14]  G. Capellá,et al.  Genetic heterogeneity of the c-K-ras locus in colorectal adenomas but not in adenocarcinomas. , 1993, Journal of the National Cancer Institute.

[15]  J. Benhattar,et al.  An improved method for rapid screening of DNA mutations by nonradioactive single-strand conformation polymorphism procedure. , 1993, BioTechniques.

[16]  B. Iacopetta,et al.  Comparison of p53 gene mutation and protein overexpression in colorectal carcinomas. , 1994, British Journal of Cancer.

[17]  G. Thomas,et al.  Association of p53 mutations with short survival in colorectal cancer. , 1994, Gastroenterology.

[18]  M. Inoue,et al.  A frequent alteration of p53 gene in carcinoma in adenoma of colon. , 1994, Cancer research.

[19]  M. Fey,et al.  Somatic mutations detected by mini- and microsatellite DNA markers reveal clonal intratumor heterogeneity in gastrointestinal cancers. , 1995, Cancer research.

[20]  P. Roy-Burman,et al.  Heterogeneity in intratumor distribution of p53 mutations in human prostate cancer. , 1995, The American journal of pathology.

[21]  N. Konishi,et al.  Intratumor cellular heterogeneity and alterations in ras oncogene and p53 tumor suppressor gene in human prostate carcinoma. , 1995, The American journal of pathology.

[22]  M. Loda,et al.  Increased incidence of p53 mutations is associated with hepatic metastasis in colorectal neoplastic progression. , 1995, Oncogene.

[23]  F. Waldman,et al.  ERBB-2 (HER2/neu) gene copy number, p185HER-2 overexpression, and intratumor heterogeneity in human breast cancer. , 1995, Cancer research.

[24]  T. Inoue,et al.  Flow cytometric analysis of the dna content in primary and metastatic lesions of colorectal cancer , 1995, Journal of surgical oncology.

[25]  K. Bland,et al.  Prognostic value of TP53 and K-ras-2 mutational analysis in stage III carcinoma of the colon. , 1995, American journal of surgery.

[26]  Y. Yuasa,et al.  Clonal Heterogeneity in Human Esophageal Squamous Cell Carcinomas on DNA Analysis , 1996, Japanese journal of cancer research : Gann.

[27]  D. Smith,et al.  Prognostic significance of p53 overexpression and mutation in colorectal adenocarcinomas. , 1996, British Journal of Cancer.

[28]  L. Secker-Walker.  Catalog of Chromosome Aberrations in Cancer , 1996, British Journal of Cancer.

[29]  K. Kinzler,et al.  Lessons from Hereditary Colorectal Cancer , 1996, Cell.

[30]  W. Giaretti,et al.  Intratumor heterogeneity of K-ras2 mutations in colorectal adenocarcinomas: association with degree of DNA aneuploidy. , 1996, The American journal of pathology.

[31]  F. Bosman,et al.  Genetic diversity at the p53 locus between primary human colorectal adenocarcinomas and their lymph‐node metastases , 1997, International journal of cancer.

[32]  A. Norman,et al.  Kirsten ras mutations in patients with colorectal cancer: the multicenter "RASCAL" study. , 1998, Journal of the National Cancer Institute.

[33]  R. Ward,et al.  Short telomeres on human chromosome 17p , 1998, Nature Genetics.

[34]  K. Kinzler,et al.  Genetic instabilities in human cancers , 1998, Nature.

[35]  R. Rosell,et al.  Allelic loss on chromosome 18q as a prognostic marker in stage II colorectal cancer. , 1998, Gastroenterology.

[36]  F. Al-Mulla,et al.  Heterogeneity of mutant versus wild‐type Ki‐ras in primary and metastatic colorectal carcinomas, and association of codon‐12 valine with early mortality , 1998, The Journal of pathology.

[37]  J. Benhattar,et al.  The type of K-ras mutation determines prognosis in colorectal cancer. , 1998, American journal of surgery.

[38]  H. Kijima,et al.  Alteration of p53 Clonality Accompanying Colorectal Cancer Progression , 1998, Japanese journal of cancer research : Gann.

[39]  M. Hawn,et al.  Prognostic significance of allelic lost at chromosome 18q21 for stage II colorectal cancer. , 1998, Gastroenterology.

[40]  T. Sugai,et al.  Analysis of subclonal expansion of colorectal carcinomas by flow cytometry , 1999, Virchows Archiv.

[41]  R. Fishel,et al.  Genomic instability: first step to carcinogenesis. , 1999, Anticancer research.

[42]  B. Dutrillaux,et al.  DNA methylation and chromosome instability in breast cancer cell lines , 1999, FEBS Letters.

[43]  R. Orecchia,et al.  Intratumor heterogeneity of chromosome 1, 7, 17, and 18 aneusomies obtained by FISH and association with flow cytometric DNA index in human colorectal adenocarcinomas. , 1999, Cytometry.

[44]  M. Hande,et al.  Telomere Length Dynamics and Chromosomal Instability in Cells Derived from Telomerase Null Mice , 1999, The Journal of cell biology.

[45]  A. Wyllie,et al.  Heterogeneity studies identify a subset of sporadic colorectal cancers without evidence for chromosomal or microsatellite instability , 1999, Oncogene.

[46]  A. Vecchione,et al.  Intratumoral heterogeneity in colorectal carcinoma: trucut sampling for DNA ploidy analysis. , 1999, Anticancer research.

[47]  J. Salisbury,et al.  Regulation and regulatory activities of centrosomes , 1999, Journal of cellular biochemistry.

[48]  J W Arends,et al.  Molecular interactions in the Vogelstein model of colorectal carcinoma , 2000, The Journal of pathology.

[49]  F. Bosman,et al.  p53 and Ki-ras as prognostic factors for Dukes' stage B colorectal cancer. , 2000, European journal of cancer.

[50]  J. Benhattar,et al.  Microdissection by exclusion and DNA extraction for multiple PCR analyses from archival tissue sections. , 2000, BioTechniques.