Canine Transmissible Venereal Tumor

CTVT is the world's oldest known cancer - a sexually transmitted tumor that has been spreading through dog populations for approximately 11,000 years. Every CTVT tumor cell today is a direct descendant of a single cancer that arose in a dog living thousands of years ago. The original dog is long dead; its cancer lives on as an essentially immortal parasite.

CTVT demonstrates that biological immortality is possible - not for the organism that created the cancer, but for the cancer itself. Over millennia, CTVT has evolved to balance virulence and transmission: too aggressive and it kills hosts before spreading; too mild and it's cleared by immune systems. The business parallel is parasitic business models that persist by extracting just enough value to survive without killing their hosts. Rent-seeking entities that have found sustainable extraction rates.