Immunohistochemical finding of α‐1‐antichymotrypsin in tissues of benign prostatic hyperplasia and prostate cancer

Abstract

Background: Ratio of free to total (F/T) prostate-specific antigen (PSA) is higher in the blood of patients with benign prostatic hyperplasia than those with prostate cancer. To clarify the difference between ratios in these two, a-1-antichymotrypsin, the major component of the bound PSA in the blood, was immunohistochemically examined. Methods: Tissues were obtained surgically via a retropubic approach from patients with benign prostatic hyperplasia (nine cases) and prostate cancer (27 cases). These samples were processed in paraffin blocks, cut into 5 mm sections and stained with antibodies against a-1-antichymotrypsin and PSA. Results:The percentage of a-1-antichymotrypsin-stained cells in prostate cancer was higher than that in benign prostatic hyperplasia (P < 0.05). Almost all of glandular and cancer cells were stained with PSA antibody. The percentage of a-1-antichymotrypsin-stained cells in prostate cancer did not correlate to histologic grade, although a-1-antichymotrypsin-stained cells were more widely scattered in high grade tissues. No correlation was found between a-1-antichymotrypsinstained cells and ratio of F/T in the blood of cancer patients. In about 20% of cancer tissues, histiocytes with positive a-1-antichymotrypsin staining were found in stroma but not in that of benign prostatic hyperplasia. Conclusions: Prostate cancer tissues are shown to have a richer environment of a-1-antichymotrypsin than those of benign prostatic hyperplasia. Some cancer tissues contained a-1-antichymotrypsin-stained histiocytes. These local events may correlate to a high amount of the bound form among total PSA in the blood of prostate cancer patients.Key words a-1-antichymotrypsin, benign prostatic hyperplasia, free to total ratio of prostate-specific antigen, prostate cancer.

The role of prostate‐specific antigen in the clinical evaluation of prostatic disease

“…4). ACT appears to be produced in small amounts in normal and BPH tissue, and in much higher amounts by prostate cancer cells [37–40]. In addition, Miller et al.…”

Change in the ratio of free‐to‐total prostate‐specific antigen during progression of advanced prostate cancer

“…Supposing cancer cells are the main source of α‐1‐antichymotrypsin in the tissues, the F/T ratio in serum might not correlate with the ratio of α‐1‐antichymotrypsin‐stained cancer cells the entire cancer cell population. However, no relationship was noticed, 22 therefore, regulation of the F/T ratio still remains to be clarified.…”

“…21 Using an immunohistochemical technique we also found a-1-antichymotrypsin-stained cancer cells in the prostate, but there was only a few similarly stained glandular cells in the tissues of patients with benign prostatic hyperplasia. 22 Moreover, some cancer tissues included a-1-antichymotrypsin-containing histiocytes in a stroma. It is known that histiocytes can pro-duce a-1-antichymotrypsin.…”

Distribution and secretory pathways of prostate specific antigen, α1‐antichymotrypsin and prostate secretory granules in prostate cancers

“…Tanaka et al . reported that cancer cells were more strongly positive for ACT than benign prostatic hyperplasia, resulting in a decreased free to total PSA ratio 21 . Wu et al .…”

“…Tanaka et al reported that cancer cells were more strongly positive for ACT than benign prostatic hyperplasia, resulting in a decreased free to total PSA ratio. 21 Wu et al reported, from their analysis of cDNA sequence data, that the peptide backbone of prostatic ACT is identical to the protein derived from the liver, and thus may be functional as a protease inhibitor. 22 From our findings, ACT is mainly seen in normal duct and cancer cells.…”