Abstract
Background—Published data are contradictory about the importance of K-ras mutations in advanced tumours and are not available for early cancers. Aims—To establish whether specific K-ras mutations are prognostic markers in early stage colorectal adenocarcinoma. Methods—The presence of K-ras exon 1 mutations were correlated with tumour recurrence in two groups of patients: group 1 was a consecutive series of patients with resected colorectal adenocarcinoma at low risk of recurrence; group 2 were patients referred for chemotherapy after relapse of previously resected early stage tumours. K-ras mutations were detected by direct sequencing of whole tissue samples in all patients and in some, the leading edge and centre of the tumour were also microdissected out individually and sequenced. Results—Mutations were present in 26 (26.5%) of 98 patients in group 1; 14 patients developed a recurrence, four (28.5%) of whom had a K-ras mutation. Seventy nine patients have not developed tumour recurrence, 22 (28%) of whom had a mutation (p=0.84). K-ras mutations were present in five of 14 patients in group 2. Microdissection did not increase the number of mutations detected. Conclusions—Individual K-ras genotypes are distributed homogeneously throughout early stage colorectal adenocarcinomas, but detection of a mutation has no apparent prognostic value.
Keywords: Dukes' stage; colorectal cancer; K-ras; microdissection
Full Text
The Full Text of this article is available as a PDF (158.3 KB).
Figure 1 .
: Polyacrylamide sequencing gel using the downstream primer showing serial dilution of wild type K-ras DNA with DNA containing a heterozygous codon 13 guanine to adenine mutation. The arrow indicates the level of an additional band which can be seen in the lanes marked "T" when 5% or more of the DNA contained the codon 13 mutation. This extra band is not seen when 100% wild type DNA is sequenced. Wild type DNA was extracted from HT29 cells and mutated DNA from LoVo cells.
Figure 2 .

: Polyacrylamide sequencing gel showing K-ras exon 1 gene sequence from patient 42. The DNA has been sequenced using both the upstream and downstream primers. An arrow indicates a G to C mutation at position 2 of codon 12 giving an amino acid change from glycine to alanine.
Figure 3 .

: Toluene blue stained 15 µm paraffin wax section of a Dukes' stage A, Astler-Coller's modification B1 colorectal adenocarcinoma with the leading edge (1) and the core (2) of the tumour removed by microdissection.
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Benhattar J., Losi L., Chaubert P., Givel J. C., Costa J. Prognostic significance of K-ras mutations in colorectal carcinoma. Gastroenterology. 1993 Apr;104(4):1044–1048. doi: 10.1016/0016-5085(93)90272-e. [DOI] [PubMed] [Google Scholar]
- Bennett M. A., Kay E. W., Mulcahy H., O'flaherty L., O'donoghue D. P., Leader M., Croke D. T. ras and p53 in the prediction of survival in Dukes' stage B colorectal carcinoma. Clin Mol Pathol. 1995 Dec;48(6):M310–M315. doi: 10.1136/mp.48.6.m310. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bos J. L. ras oncogenes in human cancer: a review. Cancer Res. 1989 Sep 1;49(17):4682–4689. [PubMed] [Google Scholar]
- Breivik J., Meling G. I., Spurkland A., Rognum T. O., Gaudernack G. K-ras mutation in colorectal cancer: relations to patient age, sex and tumour location. Br J Cancer. 1994 Feb;69(2):367–371. doi: 10.1038/bjc.1994.67. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Burmer G. C., Levine D. S., Kulander B. G., Haggitt R. C., Rubin C. E., Rabinovitch P. S. c-Ki-ras mutations in chronic ulcerative colitis and sporadic colon carcinoma. Gastroenterology. 1990 Aug;99(2):416–420. doi: 10.1016/0016-5085(90)91024-z. [DOI] [PubMed] [Google Scholar]
- Dix B. R., Robbins P., Soong R., Jenner D., House A. K., Iacopetta B. J. The common molecular genetic alterations in Dukes' B and C colorectal carcinomas are not short-term prognostic indicators of survival. Int J Cancer. 1994 Dec 15;59(6):747–751. doi: 10.1002/ijc.2910590606. [DOI] [PubMed] [Google Scholar]
- Don R. H., Cox P. T., Wainwright B. J., Baker K., Mattick J. S. 'Touchdown' PCR to circumvent spurious priming during gene amplification. Nucleic Acids Res. 1991 Jul 25;19(14):4008–4008. doi: 10.1093/nar/19.14.4008. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Finkelstein S. D., Sayegh R., Christensen S., Swalsky P. A. Genotypic classification of colorectal adenocarcinoma. Biologic behavior correlates with K-ras-2 mutation type. Cancer. 1993 Jun 15;71(12):3827–3838. doi: 10.1002/1097-0142(19930615)71:12<3827::aid-cncr2820711207>3.0.co;2-n. [DOI] [PubMed] [Google Scholar]
- Halter S. A., Webb L., Rose J. Lack of ras mutations and prediction of long-term survival in carcinoma of the colon. Mod Pathol. 1992 Mar;5(2):131–134. [PubMed] [Google Scholar]
- Kastrinakis W. V., Ramchurren N., Maggard M., Steele G., Jr, Summerhayes I. C. K-ras status does not predict successful hepatic resection of colorectal cancer metastasis. Arch Surg. 1995 Jan;130(1):9–14. doi: 10.1001/archsurg.1995.01430010011001. [DOI] [PubMed] [Google Scholar]
- Kato M., Ito Y., Kobayashi S., Isono K. Detection of DCC and Ki-ras gene alterations in colorectal carcinoma tissue as prognostic markers for liver metastatic recurrence. Cancer. 1996 Apr 15;77(8 Suppl):1729–1735. doi: 10.1002/(SICI)1097-0142(19960415)77:8<1729::AID-CNCR47>3.0.CO;2-Z. [DOI] [PubMed] [Google Scholar]
- Kinoshita T., Yokota T., Arai K., Miyajima A. Regulation of Bcl-2 expression by oncogenic Ras protein in hematopoietic cells. Oncogene. 1995 Jun 1;10(11):2207–2212. [PubMed] [Google Scholar]
- Markowitz S, Hines JD, Lutterbaugh J, Myeroff L, Mackay W, Gordon N, Rustum Y, Luna E, Kleinerman J. Mutant K-ras oncogenes in colon cancers Do not predict Patient's chemotherapy response or survival. Clin Cancer Res. 1995 Apr;1(4):441–445. [PubMed] [Google Scholar]
- McGrath J. P., Capon D. J., Smith D. H., Chen E. Y., Seeburg P. H., Goeddel D. V., Levinson A. D. Structure and organization of the human Ki-ras proto-oncogene and a related processed pseudogene. Nature. 1983 Aug 11;304(5926):501–506. doi: 10.1038/304501a0. [DOI] [PubMed] [Google Scholar]
- Minamoto T., Sawaguchi K., Mai M., Yamashita N., Sugimura T., Esumi H. Infrequent K-ras activation in superficial-type (flat) colorectal adenomas and adenocarcinomas. Cancer Res. 1994 Jun 1;54(11):2841–2844. [PubMed] [Google Scholar]
- Minamoto T., Yamashita N., Ochiai A., Mai M., Sugimura T., Ronai Z., Esumi H. Mutant K-ras in apparently normal mucosa of colorectal cancer patients. Its potential as a biomarker of colorectal tumorigenesis. Cancer. 1995 Mar 15;75(6 Suppl):1520–1526. doi: 10.1002/1097-0142(19950315)75:6+<1520::aid-cncr2820751523>3.0.co;2-l. [DOI] [PubMed] [Google Scholar]
- Moerkerk P., Arends J. W., van Driel M., de Bruïne A., de Goeij A., ten Kate J. Type and number of Ki-ras point mutations relate to stage of human colorectal cancer. Cancer Res. 1994 Jul 1;54(13):3376–3378. [PubMed] [Google Scholar]
- Moertel C. G., Fleming T. R., Macdonald J. S., Haller D. G., Laurie J. A., Goodman P. J., Ungerleider J. S., Emerson W. A., Tormey D. C., Glick J. H. Levamisole and fluorouracil for adjuvant therapy of resected colon carcinoma. N Engl J Med. 1990 Feb 8;322(6):352–358. doi: 10.1056/NEJM199002083220602. [DOI] [PubMed] [Google Scholar]
- Morrin M., Kelly M., Barrett N., Delaney P. Mutations of Ki-ras and p53 genes in colorectal cancer and their prognostic significance. Gut. 1994 Nov;35(11):1627–1631. doi: 10.1136/gut.35.11.1627. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mukhopadhyay T., Tainsky M., Cavender A. C., Roth J. A. Specific inhibition of K-ras expression and tumorigenicity of lung cancer cells by antisense RNA. Cancer Res. 1991 Mar 15;51(6):1744–1748. [PubMed] [Google Scholar]
- Oudejans J. J., Slebos R. J., Zoetmulder F. A., Mooi W. J., Rodenhuis S. Differential activation of ras genes by point mutation in human colon cancer with metastases to either lung or liver. Int J Cancer. 1991 Dec 2;49(6):875–879. doi: 10.1002/ijc.2910490613. [DOI] [PubMed] [Google Scholar]
- Schwab G., Duroux I., Chavany C., Hélène C., Saison-Behmoaras E. An approach for new anticancer drugs: oncogene-targeted antisense DNA. Ann Oncol. 1994;5 (Suppl 4):55–58. doi: 10.1093/annonc/5.suppl_4.s55. [DOI] [PubMed] [Google Scholar]
- Shimizu K., Birnbaum D., Ruley M. A., Fasano O., Suard Y., Edlund L., Taparowsky E., Goldfarb M., Wigler M. Structure of the Ki-ras gene of the human lung carcinoma cell line Calu-1. Nature. 1983 Aug 11;304(5926):497–500. doi: 10.1038/304497a0. [DOI] [PubMed] [Google Scholar]
- Sklar M. D. Increased resistance to cis-diamminedichloroplatinum(II) in NIH 3T3 cells transformed by ras oncogenes. Cancer Res. 1988 Feb 15;48(4):793–797. [PubMed] [Google Scholar]
- Sklar M. D. The ras oncogenes increase the intrinsic resistance of NIH 3T3 cells to ionizing radiation. Science. 1988 Feb 5;239(4840):645–647. doi: 10.1126/science.3277276. [DOI] [PubMed] [Google Scholar]
- Tanaka M., Omura K., Watanabe Y., Oda Y., Nakanishi I. Prognostic factors of colorectal cancer: K-ras mutation, overexpression of the p53 protein, and cell proliferative activity. J Surg Oncol. 1994 Sep;57(1):57–64. doi: 10.1002/jso.2930570115. [DOI] [PubMed] [Google Scholar]
- Urosević N., Krtolica K., Skaro-Milić A., Knezević-Usaj S., Dujić A. Prevalence of G-to-T transversions among K-ras oncogene mutations in human colorectal tumors in Yugoslavia. Int J Cancer. 1993 May 8;54(2):249–254. doi: 10.1002/ijc.2910540215. [DOI] [PubMed] [Google Scholar]
- Vogelstein B., Fearon E. R., Hamilton S. R., Kern S. E., Preisinger A. C., Leppert M., Nakamura Y., White R., Smits A. M., Bos J. L. Genetic alterations during colorectal-tumor development. N Engl J Med. 1988 Sep 1;319(9):525–532. doi: 10.1056/NEJM198809013190901. [DOI] [PubMed] [Google Scholar]
- Vojtek A. B., Cooper J. A. Rho family members: activators of MAP kinase cascades. Cell. 1995 Aug 25;82(4):527–529. doi: 10.1016/0092-8674(95)90023-3. [DOI] [PubMed] [Google Scholar]

