Prognosis of breast cancer patients by monitoring the expression of two genes

The invention is related to a method for evaluating a breast cancer patient’s risk of recurrence comprising detecting the level of CyclinG2 (Gene ID = 901) gene expression alone or in combination with Sharp1 (Gene ID = 79365) in a sample.The detection comprises measuring a signal directly related to the gene(s) expression in said sample, acquiring the signal and evaluating the risk of cancer recurrence of a breast cancer patient by: -calculating a signature score for Cyclin G2 gene expression values alone or for, preferably, both Cyclin G2 and Sharp-1 expression values in the unknown sample, wherein said signature score is defined as: being K=1 when using Cyclin G2 alone and K=2 when using both Cyclin G2 and Sharp-1, the expression level of CyclinG2 or Sharp-1 in the unknown sample i, and respectively the estimated mean and standard deviation values of the Cyclin G2 and/or Sharp-1 expression levels in a population with known clinical history, and wherein a signature score lower than zero indicates an increased risk of breast cancer recurrence.The detection may be carried out by molecular and/or immunological means, where by molecular means are meant assays based on nucleic acids such as PCR, microarray analysis or Northern-blot.The method further comprises statistical analysis of the signal through the following steps:-quality control of the acquired signal, -signal normalization; -optionally rescaling the acquired signal, and is preferably carried out by a software run on a computer.The invention further provides for a kit to evaluate Cyclin G2 expression alone or in combination with Sharp 1 and determine the risk of cancer recurrence in a sample from a breast cancer patient, said kit preferably comprising:-a CyclinG2- specific reagent, preferably a oligonucleotide consisting in a oligonucleotide comprising at least a 13-mer oligonucleotide derived from SEQIDNO:1 or its complementary sequence; -a Sharp1-specific reagent, preferably a oligonucleotide consisting in a oligonucleotide comprising at least a 13-mer oligonucleotide derived from SEQIDNO:2 or its complementary sequence;-instruction for calculating the signature score of the unknown sample and classifying the unknown sample in the minimal signature Low group when its signature score is negative or in the minimal signature High when its signature score is positive, according to calculation defined for the method above, wherein classification into the minimal signature Low group is an indication of an high risk of cancer recurrence for a breast cancer patient.According to a preferred embodiment said instruction are carried out by a software.Optionally the kit may further comprise as reference standards, CyclinG2 and Sharp1 standard expression controls High and Low, as expression values or as nucleic acid samples. Said expression values or nucleic acid samples are preferably derived respectively from a non metastatic breast cancer cell line and/or from a highly metastatic cell line.