True.
Loss of heterozygosity (LOH) refers to the loss or deletion of one functional copy of a gene or allele in a cell. In the context of tumor suppressor genes, LOH occurs when a cell that initially has one functional copy of a tumor suppressor allele undergoes deletion or loss of that functional allele, leaving only the non-functional or mutated copy. LOH can be a significant event in cancer development, as it can lead to the complete loss of tumor suppressor gene function, allowing uncontrolled cell growth and potentially contributing to the progression of cancer.
