SummaryResearchers worldwide with information about the Kirsten ras (Ki-ras) tumour genotype and outcome of patients with colorectal cancer were invited to provide that data in a schematized format for inclusion in a collaborative database called RASCAL (The Kirsten ras incolorectal-cancer collaborative group). Our results from 2721 such patients have been presented previously and for the first time in any common cancer, showed conclusively that different gene mutations have different impacts on outcome, even when the mutations occur at the same site on the genome. To explore the effect of Ki-ras mutations at different stages of colorectal cancer, more patients were recruited to the database, which was reanalysed when information on 4268 patients from 42 centres in 21 countries had been entered. After predetermined exclusion criteria were applied, data on 3439 patients were entered into a multivariate analysis. This found that of the 12 possible mutations on codons 12 and 13 of Kirsten ras, only one mutation on codon 12, glycine to valine, found in 8.6% of all patients, had a statistically significant impact on failure-free survival (P = 0.004, HR 1.3) and overall survival (P = 0.008, HR 1.29). This mutation appeared to have a greater impact on outcome in Dukes' C cancers (failure-free survival, P = 0.008, HR 1.5; overall survival P = 0.02, HR 1.45) than in Dukes' B tumours (failure-free survival, P = 0.46, HR 1.12; overall survival P = 0.36, HR 1.15). Ki-ras mutations may occur early in the development of pre-cancerous adenomas in the colon and rectum. However, this collaborative study suggests that not only is the presence of a codon 12 glycine to valine mutation important for cancer progression but also that it may predispose to more aggressive biological behaviour in patients with advanced colorectal cancer. © 2001 Cancer Research Campaign http://www.bjcancer.comIt is widely accepted that mutations in the Kirsten ras (Ki-ras) gene in patients with colorectal cancer develop early in the progression from adenoma to carcinoma. Our first collaborative study including 2721 patients, clarified that Ki-ras mutations are not only 692

The potent and selective killing activity of Ad-mda7 in cancer cells but not in normal cells makes this vector a potential candidate for cancer gene therapy.

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The HLA-CW2 antigen of the B lymphoblastoid cell line BRI 8 is structurally homologous to the HLA-A and B antigens as judged by various criteria. Each antigen comprised a glycosylated polypeptide of 43 000 molecular weight that is noncovalently associated with beta2-microglobulin (beta2m). Some small differences in molecular parameters were, however, revealed. Thus, the deoxycholate-solubilized HLA-CW2 antigen sedimented at the same rate as the HLA-A antigens but at a slightly faster rate than the HLA-B antigens. This variation is apparently is apparently due to different amounts of bound deoxycholate. Also, whereas essentially all of the HLA-A and B antigens and about half of the HLA-CW2 antigen were adsorbed strongly by Lens culinaris lectin-Sepharose, the remaining HLA-CW2 antigen was bound much more weakly and did not require sugar for elution. This difference reflects some structural heterogeneity in the carbohydrate moiety of the HLA-CW2 antigen. The results of various studies suggest that the HLA-CW2 antigen is expressed to a lower extent than the HLA-A or B antigens and that essentially all of the beta2m of the BRI 8 plasma membrane is associated with the HLA-A, B and C alloantigenic polypeptides.

1. The mucoprotein from pig gastric mucus has been purified by equilibrium centrifugation in a CsCl gradient. 2. This procedure removes the non-covalently bound protein, which is closely associated with the mucoprotein and not easily removed from it by gel filtration. 3. The purified mucoprotein is separable by gel filtration into a high-molecular-weight mucoprotein A (mol.wt. 2.3x10(6)) and a low-molecular-weight mucoprotein B/C (mol.wt. 1.15x10(6)). 4. These two mucoproteins have the same chemical analysis namely fucose 11.3%, galactose 26%, glucosamine 19.5%, galactosamine 8.3% and protein 13.6%. 5. Mucoprotein A contains 3.1% ester sulphate. 6. These mucoproteins are isolated without enzymic digestion and have a higher protein content than the blood-group-substance mucoproteins from proteolytic digestion of gastric mucus. Detailed amino acid analysis shows that the extra protein in the non-enzymically digested material is composed of amino acids other than serine and threonine. 7. Mucoproteins A and B/C contain respectively 130 and 9 half-cystine residues per molecule of which about 78 and 6 residues are involved in disulphide linkages. 8. Cleavage of these disulphide linkages by mercaptoethanol splits both mucoproteins into four equally sized subunits of mol.wt. 5.2x10(5) for mucoprotein A and 2.8x10(4) for mucoprotein B/C. 9. The sole N-terminal amino acid of mucoprotein A is aspartic acid, whereas mucoprotein B/C has several different N-terminal amino acid residues.

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Six murine monoclonal antibodies to Leishmania tropica major have been prepared and the properties of these antibodies studied. Two (WIC 79.3 and 79.7) were L. tropica major species-specific and bound to promastigote cell surfaces, to parasitized macrophages, but not isolated amastigotes. No evidence was found for the production of antibody to the antigenic determinants recognized by WIC 79.3 or 79.7 during L. tropica major infections in mice and hamsters. One antibody (WIC 79.1) bound to sub-cellular organelles of Leishmania species but to a different sub-cellular organelle of Trypanosoma cruzi. Two others bound to the flagellum, one (WIC 79.2) to all Leishmania species, T. cruzi and Trypanosoma brucei, the other (WIC 79.4) only of L. tropica major and L. donovani species. One antibody (WIC 79.5) was directed against an unknown internal antigen found in all Leishmania species and T. cruzi.

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