Further, stratifying by therapy (starting or on taxane vs. abiraterone/enzalutamide), we see that both AR amplification (yes/no) (Kaplan-Meier log-rank test, chi-square = 21.9, p<0.0001; Figure 5D) or cfDNA tumor content (Kaplan-Meier log-rank test, chi-square = 18.9, p = 0.0003; Figure 5E) again show significant differences in time on therapy, suggesting cfDNA detectable AR amplification (and high cfDNA tumor content) may be a potentially prognostic marker for resistance to both second generation anti-androgen therapy and taxane chemotherapies. This evidence concerns the gene AR and neoplasm.