Method for the Prediction of the Risk Potential for Cancerous Diseases and Inflammatory Intestinal Diseases and Corresponding Tests

Abstract

The invention relates to a method for the prediction of the risk potential and / or diagnosis of cancerous diseases or inflammatory intestinal diseases, whereby a DNA sample is tested for the presence of polymorphic UGT1A7 allele. A positive result for a mutation is a positive indication of a sensitivity to cancerous diseases. A prediction of sensitivity to an inflammatory intestinal disease can similarly be made. A PCR amplification of the exon 1, by means of the DNA sample with subsequent sequence analysis is carried out in the method and the determined sequence compared with that of the wild type and the polymorphic allele. The presence or lack of mutations is monitored by means of sequencing the corresponding cDNA using automated fluorescent dye sequencing. The test arrangement for said method requires genetic detection reagents, namely the required primer or cDNAs, on a stationary support in a pre-prepared arrangement or sequence for reading off the results. The recombinant UGT1A7 enzymes are also used for therapeutic purposes.

Description

FIELD OF THE INVENTION [0001] The invention relates to a method for predicting the potential risk of carcinomas and inflammatory bowel diseases and for diagnosing these disorders. The invention primarily relates to a method for estimating the potential risk of colorectal carcinomas. The invention further relates to diagnostic tests on DNA samples from an individual to be investigated, and to the use of new polymorphic forms of the UGT1A7 gene for the metabolic characterization of medicaments, especially of tumor therapeutic agents. BACKGROUND OF THE INVENTION [0002] The current assumption is that the risk of cancer is determined by a genetic predisposition and by environmental effects including exposure to carcinogenic substances. [0003] It has therefore frequently been assumed that there is an association between genetic polymorphisms of carcinogen-metabolizing enzymes and the development of a cancer. However, specific, statistically confirmed associations are difficult to find bec...

AI Technical Summary

Benefits of technology

[0020] One advantage of the invention is that patients can be assigned at an early date to appropriate risk groups and referred for preventive treatment, leading to an improvement in early detection.

[0021] A further advantage of the invention is that the method can also be used for diagnosis. One improvement in diagnosis is a possibility of obtaining even more quickly a clear result on the condition of the patient and accordingly of giving treatment earlier and in a more targeted manner. Early detection and immediate therapy are of crucial importance in particular for carcinomas. CRC can if detected early be prevented or cured in most cases.

[0022] Genomic DNA from lymphocytes is preferably used for an investigation. The genomic DNA can be isolated from a sample of the subject's blood by methods of column chromatography and chemical processing. This genomic DNA, which represents the genotype of the person to be investigated, forms the basis for all further genetic test strategies.

[0023] There is firstly a general provision for the DNA obtained from the patient to be amplified by the polymerase chain reaction.

[0024] A possibility for this in a first embodiment of the invention is to carry out a PCR amplification of the complete exon 1 of the UGT1A7 gene (about 855 base pairs), followed by a sequence analysis. The sequence found can be analyzed in a suitable way, i.e. be compared with the sequence of the wild type and of the UGT1A7 alleles UGT1A7*2 (SEQ ID NO: 19), UGT1A7*3 (SEQ ID NO: 20) and UGT1A7*4 (SEQ ID NO: 21) which are relevant to this method.

[0025] In another embodiment, the only cDNA fragments to be amplified are those intended to provide information about the mutations which are sought. The DNA sample is therefore preferably treated with specific primer pairs, of which in each case one binds upstream and one binds downstream of the relevant mutated DNA regions around codons 11, 129 / 131 or 208, and cDNA fragments which match corresponding fragments of the wild-type allele or of the polymorphic alleles are generated in a polymerase chain reaction, and the presence of mutations at codons 11, 129, 131 and / or 208 is subsequently detected with the aid of sequencing and / or hybridization techniques.

Problems solved by technology

However, specific, statistically confirmed associations are difficult to find because the metabolizing cannot be equated with a detoxification.

For predicting the risk of cancer it is therefore insufficient just to detect genetic modifications; on the contrary, it is necessary to know that the change leads to clearly adverse metabolic consequences.

A further problem in finding such an association is that the human metabolism is very complex and an enormous number of substances, including metabolites, proteins and in particular also enzymes, might be suitable markers for a risk of cancer.

It was therefore necessarily doubtful whether an unambiguous estimation of the risk on the basis of a genetic predisposition is in fact possible.

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