A method for identifying the presence of a chromosomal aberration in the tumor sample cells in at least one of several genes from the next generation sequencing data analysis of a pool of patient tumor samples comprising at least two analyzed genes, with a variant classification data processor module which operates solely on variant calling information from samples comprising a mix of germline and somatic cells and for each possible sample purity value p, in which a combination of at least two genomic alterations have caused its biallelic loss of function, the said data processor module performs a method comprising: - acquiring a variant calling information of the next generation sequencing of the pool of patient tumor samples comprising germline and somatic cells, the variant calling information comprising for each patient a list of SNPs genomic variants in at least two genes to be analyzed; - selecting, in the list of genomic variants, a set of putative germline heterozygous SNPs by comparing the list of genomic variants to a reference human genome variant database; - for each possible value of sample purity p, a sample purity p being a ratio of somatic DNA material to germline DNA material in the overall FFPE sample, fitting a mixture model to the observed variant fraction distribution of said set in the variant calling data, the modeled variant fraction distribution values being calculated as a function of the sample purity p; - inferring an optimal sample purity p optimal as the possible sample purity p for which the mixture model best fits the observed variant fraction distribution of said set; - for each gene to be analyzed: o selecting, in the plurality of putative germline heterozygous SNPs, a subset of putative germline heterozygous SNPs located in the gene to be analyzed, o inferring the presence of a chromosomal aberration in said tumor sample cells by comparing, on at least said subset, the observed variant fraction distribution with the predicted variant fraction distribution for each possible chromosomal aberration, the predicted variant fraction distribution values being calculated as a function of the optimal sample purity p optimal. - acquiring a variant calling information of the next generation sequencing of the pool of patient tumor samples comprising germline and somatic cells, the variant calling information comprising for each patient a list of SNPs genomic variants in at least two genes to be analyzed; - selecting, in the list of genomic variants, a set of putative germline heterozygous SNPs by comparing the list of genomic variants to a reference human genome variant database; - for each possible value of sample purity p, a sample purity p being a ratio of somatic DNA material to germline DNA material in the overall FFPE sample, fitting a mixture model to the observed variant fraction distribution of said set in the variant calling data, the modeled variant fraction distribution values being calculated as a function of the sample purity p; - inferring an optimal sample purity p optimal as the possible sample purity p for which the mixture model best fits the observed variant fraction distribution of said set; - for each gene to be analyzed: o selecting, in the plurality of putative germline heterozygous SNPs, a subset of putative germline heterozygous SNPs located in the gene to be analyzed, o inferring the presence of a chromosomal aberration in said tumor sample cells by comparing, on at least said subset, the observed variant fraction distribution with the predicted variant fraction distribution for each possible chromosomal aberration, the predicted variant fraction distribution values being calculated as a function of the optimal sample purity p optimal. o selecting, in the plurality of putative germline heterozygous SNPs, a subset of putative germline heterozygous SNPs located in the gene to be analyzed, o inferring the presence of a chromosomal aberration in said tumor sample cells by comparing, on at least said subset, the observed variant fraction distribution with the predicted variant fraction distribution for each possible chromosomal aberration, the predicted variant fraction distribution values being calculated as a function of the optimal sample purity p optimal.