Abnormal G-actin content in single prostate cells as a biomarker of prostate cancer.

The distribution of altered G-actin was investigated in prostatic cells obtained by fine needle aspiration (FNA) from 27 excised prostate glands obtained during radical prostatectomy. FNA, which was used to obtain single cells for image analysis, sampled in the region of any nodules and in grossly normal areas of the contralateral lobes. Quantitative fluorescence-image analysis was used to assay the amount of G-actin in individual cells. Abnormal G-actin, a precursor cytoskeletal protein representing cytoskeletal rearrangements accompanying cellular transformation, was associated with the presence of adenocarcinoma in 22 of 27 specimens from the dominant nodule, but only 3 of 20 in the grossly normal specimens (P<.0001). The mean G-actin content of all samples from the dominant nodule was 113.2+/-6.87 and 69.57+/-4.47 from the grossly normal area, the difference being significant at P<.0001. Altered G-actin was not associated with Gleason score (P = .95), grade (P = .26), stage (P = .058), or tumor volume (P = .32), thereby indicating it is a general marker for prostate adenocarcinoma.