Neuroblastomas presenting in the first year of life: epidemiological differences from those presenting at older ages

In a population-based study comparing neuroblastomas presenting in the first year of life with those presenting at older ages, the following aggregate associations were found: Presentation of the disease before 1 year of age was associated with (i) multiorigin of primary tumors, (ii) young parental age, (iii) lower socioeconomic circumstances, and (iv) complications during pregnancy. Presentation after the first year of life was associated with (i) unifocal disease, (ii) a higher frequency of hereditary diseases in the family, and (iii) parental age above 34 years. Maternal occupation in medical services appeared to be associated with multiorigin of tumors; otherwise, the occupations held by the parents at the time of the child's birth did not differ between the two groups of patients. We hypothesized that differences between the two groups of patients might point to (i) risk factors for germ line mutations and (ii) genomic imprinting. An alternative explanation of the differences could, however, be that neuroblastoma represents at least two distinct disease entities.