Who is the antagonist in Age of Iron by J. M. Coetzee?

There are actually two antagonists in the novel and neither is a character. The first antagonist, is the cancer spreading through Mrs. Curren's body..... an illness that fills her with a sense of urgency to stand up for what she believes in. The other antagonist, apartheid, is the cancer found within Mrs. Curren's homeland...... South Africa.