Cardiac myxoma, the most common primary tumor of the heart, has a variable clinical presentation. It has been proposed that apoptosis (programmed cell death) is critical in several cardiovascular diseases but not cardiac myxoma. This study was designed to identify and characterize apoptosis in cardiac myxoma.
A retrospective study was conducted between December 1976 and June, 2003, including 103 consecutive patients with cardiac myxoma whose tumors had been surgically excised. Apoptosis was studied using TUNEL and DNA fragmentation assays and by immunochemical studies for activation of caspase-3 and TNFα] in tumor tissue. We analyzed samples from 32 randomly selected cardiac myxoma patients.
Of the 103 myxoma patients, 58 were women, 45 men (age 39 ± 21 y). Clinical presentations included asymptomatic (41%), dyspnea (33%), stroke (22%), chest pain (7%), fever (6%), syncope (5%) and tricuspid regurgitation (72%). Ninety-two myxomas were in left atrium, four recurrent myxomas and eight other myxomas were located elsewhere. These Myxomas did not differ in terms of pathological scores including vascular proliferation, inflammation, cellularity, hyaline, calcification and thrombosis. Most (85%) were characterized by extensive apoptosis but none involved activation of caspase-3.
Apoptosis is very common in myxomas but does not involve caspase-3. Our results indicate that apoptosis has a novel pathological pattern in cardiac myxomas, a pattern that does not include activation of the caspase-3 pathway. These findings should help identify and characterize any possible role for apoptosis in the development of cardiac myxoma.
The clinical implications of apoptosis in cardiac myxoma require further evaluation, this finding creates the possibility of treatments based on monoclonal antibodies or vaccination strategies, like those that already have been established for other tumor entities.
P. Chu, None.