Principal component analysis (PCA) of SNP/CN markers separates plasma DNA of presurgical breast cancer patients from healthy female controls. (A) PCA profiles of 15 presurgical breast cancer patients and eight healthy controls showing clear separation of the plasma DNA profiles. The plasmas of healthy female controls clustered with normal leukocytes (blue circles). (B) PCA profiles of 50 patients on follow-up, showing separation of normal leukocytes and tumor DNA, with P1 and P2 samples scattered between these. Control indicates healthy female controls; presurgical, plasma of presurgical breast cancer patients; L, normal leukocyte DNA; P1 and P2, first and second plasma samples of patients on follow-up; and T, FFPE tumor DNA.
