Who are the Kadmins from Cancer Ward and what is their importance?

The Kadmins are friends of Oleg from Ush-Terek. They are symbolic of a typical exiled couple in the Soviet Union of that time. As a result of a mistake by the mother-in-law, the couple are sentenced to ten years in Siberia, then exiled to one of the remote republics. Oleg observes that the couple make the best of a truly horrible situation.