A previously characterized single nucleotide polymorphism (rs3130932) in the translation initiation codon of the OCT4B isoform of the human OCT4 gene, ATG → AGG, is expected to hamper its expression in individuals carrying the AGG genotype. A case-control association study was conducted to validate the AGG genotype as a risk factor for tumour development. Blood samples were collected from 221 female patients with breast cancer, 100 female patients with ovarian cancer, 109 male patients with lung cancer and 553 age-matched and sex-matched healthy individuals. DNA was tested by restriction fragment length polymorphism-PCR for the presence of rs3130932. Statistical association studies were carried out to investigate any association between hOCT4 genotypes and the onset of cancer. Genotypic and allelic statistical analyses led to no significant case-control differences at a P value of less than 0.05 in all different types of cancer, thus showing no significant correlation of the hOCT4 genotypes tested with breast, ovarian or lung cancer risk. The AGG genotype in rs3130932 is not associated with increased (or decreased) cancer risk in homozygous individuals. Research focusing on the elucidation of the biological roles of each OCT4 isoform is further warranted.