Trisomy 7 accumulates with age in solid tumors and non-neoplastic synovia

Trisomy 7 is a common finding in benign and malignant solid tumors, in seve ral non-neoplastic lesions (for example, osteoarthritis and rheumatoid arth ritis), and in apparently normal tissues as well. suggesting that the occur rence of +7 might be associated with factors other than the disease process itself. To find out whether the frequency of +7 varies with a patient's ag e, we cytogenetically analyzed short-term-cultured synovial samples from el derly persons without signs of arthritis and from young patients affected b y juvenile chronic arthritis (JCA). In normal synovia, gain of a chromosome 7 was present as a clonal change in five of 10 cases and in single cells i n four of the five remaining cases. In synovia from patients with JCA, cell s with +7 were detected in only one of nine cases, representing the oldest patient in the series. Furthermore, we reviewed the cytogenetic literature on tumors of the brain. breast, colon, kidney, lung, skin, thyroid, and upp er aerodigestive tract. In the majority (six of eight) of these tumor types . the frequency of cases displaying a clone with +7 as the sole aberration increased with age. Taken together, the results presented here suggest that the acquisition of trisomy 7 in some neoplastic and non-neoplastic tissues might be associated with age rather than with disease. The finding of a co mpletely different frequency distribution in two of the tumor types (tumors of the brain and the thyroid gland), however, emphasizes the heterogeneity of +7 and indicates that other, possibly tissue-specific, factors might in fluence the occurrence of this mutation. (C) 2001 Wiley-Liss. Inc.