PSA mRNA in circulating tumour cells a potential new biomarker for prostate cancer progression

Levels of prostate specific antigen (PSA) mRNA in circulating tumour cells (CTCs) can be used alongside serum PSA protein levels to refine the assessment of disease progression in patient with metastatic castration-resistant prostate cancer (mCRPC), a new study has found.

The study included 30 patients with local nonmetastatic PC (median age 71 years), 10 with metastatic hormone-sensitive PC (mHSPC; median age 75 years), and 75 with mCRPC (median age 75 years). Droplet digital polymerase chain reaction was used to measure PSA mRNA in CTCs. Spearman correlation analysis was used to evaluate the relationship between serum PSA and PSA mRNA in CTCs.

CTC expression of PSA mRNA was detected in 30 percent of patients with localized cancer, as opposed to 60 percent and 65.3 percent of comparators with mHSPC and mCRPC. Notably, in a parallel group of nine healthy donors, used as controls, 0 percent showed such expression levels.

According to researchers, these findings could suggest that even the mere detection of PSA mRNA could provide clues about disease progression.

Notably, there was a strong and significant correlation between serum PSA and PSA mRNA in CTCs only in the mHSPC (R, 0.532; p=0.041) and mCRPC (R, 0.566; p=0.025) groups. No such association was documented in patients with localized PC (R, 0.064; p=0.512).

“CTC-based PSA mRNA could be used as a new biomarker along with serum PSA protein in the metastatic stages of PC. This finding suggests that high-quality CTCs can be used as a complementary tool to realize precision medicine in advanced PC,” the researchers said.