The simple notion is that you want long telomeres to resist aging. Cancer cells &quot;want&quot; long telomeres to maintain their &quot;cellular immortality&quot;, their ability to divide indefinitely. From Wikipedia:<p>&quot;Telomeres are critical for maintaining genomic integrity and studies show that telomere dysfunction or shortening is commonly acquired during the process of tumor development. Short telomeres can lead to genomic instability, chromosome loss and the formation of non-reciprocal translocations; and telomeres in tumor cells and their precursor lesions are significantly shorter than surrounding normal tissue.&quot;[0]<p>&quot;Cancer cells require a mechanism to maintain their telomeric DNA in order to continue dividing indefinitely (immortalization). A mechanism for telomere elongation or maintenance is one of the key steps in cellular immortalization and can be used as a diagnostic marker in the clinic. Telomerase, the enzyme complex responsible for elongating telomeres through the addition of telomere repeats to the ends of chromosomes, is activated in approximately 80% of tumors.&quot;[0]<p>It&#x27;s not as simple as long vs short.<p>0. <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Telomere#Cancer" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Telomere#Cancer</a>