"the brakes" You can think of tumor suppressor genes as "the brakes" in a cell. This means that they stop a cell from dividing "too fast". This is opposed to oncogenes which are "the gas" and act to make cells divide faster. N-myc is a type of oncogene.
Genes that promote. Or cause ancer are called 'oncogenes', c- or n- myc dyregulate gene functions leading to burkitt's lymphoma and neuroblastoma. Tumor suppressor genes can protect from cancer, and when they are "knocked out" can lead to cancer, rb-gene, lives on chromosme 13, can be changed/mutated leading to retinoblastoma, and its deficiency in cell-cycle regulation is found in 90+% of small cell lung ca.