Abstract 3186: Increased number of mast cells infiltrating in non-malignant biopsy is associated with detection of prostate cancer
Authors: Takayama Hitoshi , Hatano Koji , Satoh Mototaka , Kawashima Atsunari , Mukai Masatoshi , Nagahara Akira , Nakai Yasutomo , Nonomura Norio 
Published: June 2012

INTRODUCTION AND OBJECTIVE: Prostate cancer (PCA) is one of the most common malignancies. Prostate-specific antigen (PSA) is currently the most useful serum tumor marker for detecting PCA. However, because of the low specificity of PSA, many patients undergo unnecessary needle biopsies of the prostate. The discovery of new predictors is essential to establish appropriate repeat biopsies. Tumor cells are surrounded by inflammatory cells such as macrophages, lymphocytes, neutrophils and mast cells(MCs). Inflammatory cell infiltrates may contribute to tumor progression by producing angiogenic factors. MCs are potent stimulators of angiogenesis, and condition cancer growth and development of the metastasis. In the present study, infiltration of MCs in non-malignant biopsy specimens was evaluated as a possible predictive value for PCA.

METHODS: These reviews were evaluated for 125 patients ranging from 51 to 82 years (median, 69 years), who received repeat needle biopsies of the prostate and were diagnosed as non-malignant during first biopsy. Of these, 40 (32.0%) were positive for cancer during second or third biopsy. MCs was immunohistochemically labeled using a mast cell tryptase monoclonal antibody. For systematic counting, 6 ocular measuring fields were randomly chosen under a microscope at a power of×400 within first negative biopsy specimens.

RESULTS: Serum PSA levels measured by the immunoenzymatic assay from 1.70 to 43.18 ng/ml (median, 8.30 ng/ml) at first biopsy. Of these, 30 (32.0%) were positive for cancer during second, third or fourth biopsy. Serum PSA levels ranged from 1.90 to 52.68 ng/ml (median, 10.01 ng/ml) at the time of biopsy of detection of PCA. The period between the date of first biopsy and diagnosis of PCA ranged from 4.1 to 70.1 months (mean, 25.7 months).There were no significant differences in PSA at first biopsy, age and interval of previous and subsequent biopsies, between negative and positive cases for cancer. However, in PSA at first and repeat biopsy, there were significant differences between patients with or without cancer (P = 0.014, 0.002). MCs were observed in all specimens tested. Median count of MCs in each case was 11. MCs count in patients with cancer was higher than in those without cancer (P &lt; 0.001). Frequency of PCA in high MCs group (≥ 11) (54.5%) was much higher than that in low MCs group (&lt; 11) (12.5%) (P &lt; 0.001). Frequency of PCA in high PSA group (≥ 9.0) (43.8%) was much higher than that in low PSA group (&lt;9.0) (20.5%) (P = 0.015). CONCLUSION: Increased number of Mast cells infiltrating in non-malignant biopsy Is Associated with Detection of PCA.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3186. doi:10.1158/1538-7445.AM2011-3186