What is haploinsufficiency? How might it affect cancer risk?

The term in genetics that explains the function of the dominant gene in the representation of diploid organisms is haploinsufficiency. In this condition allele which is of wild-type will have only single copy at a locus with different alleles in the fusion of heterozygous and produce the insufficient phenotypic condition. 

The condition in which production of total gene produced by the cell is half than the normal and it will not be sufficient for the proper functioning of the cell is called haploinsufficiency. The recessive trait of the heterozygous individual will directly be affected by the haploinsufficiency.

In some cases, a larger amount of gene product is required as compared to normal which will reflect haploinsufficiency. It will also affect the risk of cancer in individuals like in RB tumour suppressor genes, a normal phenotype of the cell has only one functional copy but there will be no copy reserved in the cell for backup. The formation of a cancer cell will occur when the millions of retina cells will undergo mutation and leave only single wild-type allele. 

Hence, this will show that haploinsufficiency of RB is related to the phenotype of cancer predisposition.