Final answer:
True, Telomerase is an enzyme expressed in most cancer cells, playing a role in their ability to divide uncontrollably. It helps maintain chromosome ends, known as telomeres, and its inhibition is being researched as a potential cancer therapy.
Step-by-step explanation:
The statement that telomerase is expressed in 90% of all cancers is True. Telomerase is an enzyme typically active in germ cells, adult stem cells, and notably in many cancer cells. The enzyme acts to maintain the ends of chromosomes, known as telomeres, and thereby plays a crucial role in cellular aging and division. When dysfunction occurs, as in the majority of cancer cells, telomerase becomes active even when telomeres are shortened, which helps these cancerous cells to proliferate uncontrollably. The discovery of its role in cell reproduction, particularly in cancer cells, was significant enough to grant Elizabeth Blackburn a Nobel Prize in 2009. Current research is investigating how inhibiting telomerase in cancer therapy could potentially stop the division of cancerous cells. Conversely, its reactivation has potential for treating age-related diseases and conditions.