Method of determining a chemotherapeutic regimen based on ERCC1 expression
The present invention relates to prognostic methods which are useful in medicine, particularly cancer chemotherapy. The object of the invention to provide a method for assessing ERCC1 expression levels in fixed or fixed and paraffin embedded tissues and determine a platinum-based chemotherapy by examination of the amount of ERCC1 mRNA in a patient's tumor cells and comparing it to a predetermined threshold expression level. More specifically, the invention provides to oligonucleotide primer pair ERCC1 and methods comprising their use for detecting levels of ERCC1 mRNA.
1. A method of treating a tumor with a platinum-based chemotherapeutic regimen comprising:
(a) obtaining a tissue sample of the tumor and fixing the sample, to obtain a fixed tumor sample;
(b) isolating mRNA from the fixed sample in the presence of an effective amount of a chaotrophic agent by first heating the tissue sample in a solution comprising an effective concentration of a chaotrophic compound to a temperature in the range of about 50 to about 100° C. for a time period of 5 to 120 minutes and recovering said mRNA from said chaotropic solution; and
(c) subjecting the mRNA to amplification using a pair of oligonucleotide primers capable of amplifying a region of the Excision Repair Cross-Complementing 1 (ERCC1) gene, to obtain an amplified sample;
(d) determining the amount of ERCC1 mRNA relative to the quantity of an internal control gene's mRNA; and
(f) treating the tumor, wherein the treatment comprises providing a platinum-based chemotherapeutic regimen comprising a genotoxic agent when the determined gene expression level for ERCC1 gene is below a predetermined threshold value.
2. The method of claim 1 wherein the pair of oligonucleotide primers consists of SEQ lID NO: 1 or an oligonucleotide about 80% identical thereto and SEQ ID NO:2 or an oligonucleotide primer about 80% identical thereto.
3. The method of claim 1 wherein, the tumor is a non-small-cell lung cancer (NSCLC) tumor.
4. The claim 1 wherein, the genotoxic agent is gemcitabine, cisplatin or a combination thereof.