The telomeric end structures of the DNA are known to contain tandem repeats of TTAGGG sequence boundwith specialised protein complex called the “shelterin complex”. It comprises six proteins, namely TRF1, TRF2,TIN2, POT1, TPP1 and RAP1. All of these assemble together to form a complex with double strand and singlestrand DNA repeats at the telomere. Such an association contributes to telomere stability and its protection fromundesirable DNA damage control-specific responses. However, any alteration in the structure and function ofany of these proteins may lead to undesirable DNA damage responses and thus cellular senescence and death.In our review, we throw light on how mutations in the proteins belonging to the shelterin complex may lead tovarious malfunctions and ultimately have a role in tumorigenesis and cancer progression.