Cathepsin B expression in prostate cancer of native Japanese and Japanese-American patients: An immunohistochemical study

Akhouri A Sinha, Jenifer L. Morgan, Konjit Betre, Michael J Wilson, Chap T Le, Leonard S. Marks

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Background: Japanese-American (J-A) men who have immigrated to the U.S.0A. and acquired the Western lifestyle usually have more invasive prostate cancer (PCa) than native Japanese (NJ) living in Japan. The specific reasons for these differences remain unknown. The objective of this study was to examine immunostainings of cathepsin B (CB) and its endogenous inhibitor stefin A (SA) in tissue microarray (TMA) and radical prostatectomy (RP) tissue sections in the hope of obtaining insights into the invasiveness of PCa in Japanese patients. Patients and Methods: TMA and RP sections were evaluated in 50 men (25 NJ and 25 J-A) for CB and SA reaction products. The CB and SA immunostainings were imaged directly from microscope slides to a computer using a high performance charge coupled device (CCD) digital camera, quantified using Metamorph software, analyzed using the two-sample t-test, and confirmed by multiple regression analysis. Results: The CB and SA proteins were localized in the carcinomatous glands and isolated cancer cells in the TMA and RP sections. The Gleason scores and pre-surgery serum total prostate-specific antigen (PSA) levels did not differ significantly in the NJ and J-A patients (p=0.14, p=0.16, respectively). The Chi-square analysis of clinical stage versus place of birth showed that the NJ patients had significantly more T2a and T2b clinical stages than the J-A patients who had more advanced T2c and T3a stages (p=0.003). The CB and SA immunostainings and their ratios in Gleason score 6 tumors did not show any difference, but the CB:SA ratios in score ≥7 tumors approached significance levels. Conclusion: The overall matching of specimens according to the Gleason grade/score, pre-RP serum total PSA levels, clinical stage and age prior to evaluation of immunostainings greatly minimizes subjectivity associated with the evaluation of markers in this ethnic sub-population of PCa patients. CB and SA immunestaining is similar in Japanese patients who have organ-confined and moderately-differentiated PCa. Analysis of the reaction product data provides indirect evidence that invasiveness of PCa is similar in the two Japanese patient populations.

Original languageEnglish (US)
Pages (from-to)2271-2277
Number of pages7
JournalAnticancer Research
Issue number4 B
StatePublished - Jul 2008


  • Cathepsin B
  • Gleason grade
  • Inhibitor stefin A
  • Prostate cancer
  • Tissue microarray


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