Assessment of tracer 99mTc(V)-DMSA uptake as a measure of tumor cell proliferation in vitro.

Purpose: To examine whether (99m)Tc(V)-DMSA could be used as a non-invasive measure of cancer cell proliferation.

Methods: Human breast cancer MCF-7, MDA-MB-231 and pII, and prostate cancer PC-3 cell lines were grown to 30, 50 and 100% confluency and pulsed with (99m)Tc(V)-DMSA in media for 60 min at 37°C. DNA synthesis was analysed by quantification of the S phase using flow cytometry, [methyl-(3)H]thymidine incorporation and expression of proliferation markers PCNA and Ki-67 using realtime PCR. One way ANOVA was used to compare groups.

Results: In all cell lines rates of (99m)Tc(V)-DMSA uptake were inversely related to cell density. This was paralleled by similar trends in S phase proportions, [methyl-(3)H]thymidine incorporation and expression of PCNA and Ki-67.

Conclusion: Rates of (99m)Tc(V)-DMSA uptake into different types of tumour cells correlate well with cell density that is useful as a non-invasive measure of tumour cellular proliferation in vivo.