At this moment, the most cancerous is the one that white nationalist in EU/USA/Australia who are trying to fight the Muslim invasion, woke culture and communism believe in.
They believe Christianity is their culture, is their heritage, but is in reality inviting them back to the matrix, the same matrix who was created by the Jews, and who created Islam, communism and woke culture.
Real Christianity is about turning the other cheek and loving your enemies, who sees no difference between races, as each human is equal in front of the abrahamic god, while, at the same time, the Jew is higher in importance than Gentiles.
Cancerousness is not in how bad it is, or in the worst, animalistic expression of Christianity, but in how subtle it is. Cancer is basically your own cells who become hostile to your own body, because they are ill. The worst part of it is in how accepted it is, and how much we, as a society, let it determine the morals and ethics we believe in.
The most cancerous form of Christianity is in it's subtlety.