The association between malignant tumors and chromosomal abnormalities come from the alteration of the genes that control celular growth, this changes may occur in different levels, one of them is the chromosome mutation, or aneuploidy, the presence of an abnormal number of chromosomes, happends when the one DNA nucleotide is affected, and the mitosis doesn´t ocurr properly, letting the chromosomes multiply a fragment usually with oncogenes, the gen responsable of transformating normal cells into malignant ones