Expression of proto-oncogenes, genes for muscle specific isoforms and heat shock protein (HSP) -70 gene in hypertrophied cardiac muscles from patients with atrial septal defect or tetralogy of Fallot.

Studies on the expression of proto-oncogenes and muscle specific genes in hypertrophied human hearts have shown that proto-oncogenes such as c-myc, c-fos and c-ras are activated in both atrial and ventricular tissues of patients with atrial septal defect (ASD) and tetralogy of Fallot (TOF). Although the expression of muscle specific genes such as MLC2 and skeletal alpha-actin are induced the expression of tissue specific cardiac actin remained the same in both the control and diseased tissues. Further, an increased synthesis of messengers of heat shock protein gene-HSP70 was observed in the ventricular tissues of TOF patients, with out much of a change in atrial tissues of patients with ASD.