Kiyoshi Fujinami

Telomerase Activity in Primary Prostate Cancer

PURPOSE Telomerase activity has been detected in a wide variety of human tumor types. We analyzed the telomerase activity in association with the acquisition of prostate cancer. MATERIALS AND METHODS Telomerase activity in prostate tissues was examined by PCR-based telomeric repeat amplification protocol (TRAP) assay. RESULTS Among 31 primary prostate cancers, 28 tissue samples (90%) displayed telomerase activity. The relative level of telomerase activity was associated with the pathological differentiation. High levels of telomerase activity were more frequently detected in poorly differentiated prostate cancer. None of the 10 samples taken from prostates with benign prostatic hyperplasia (BPH) or normal prostates expressed telomerase activity. In another 10 BPH samples obtained from prostate tissue adjacent to cancerous tissue, one of 10 samples (10%) showed weak telomerase activity. Furthermore, we investigated this activity in human prostate cancer cell lines (PC-3, LNCaP, and DU145) and all showed very high activity compared to normal human tissue samples. Four lymph nodes and one bone metastasis also exhibited extremely high telomerase activity. CONCLUSIONS The present results indicate that telomerase activity might be a marker for detecting malignancy of the prostate and evaluating the malignant potential of prostate cancer.

ETS family-associated gene fusions in Japanese prostate cancer: analysis of 194 radical prostatectomy samples

The incidence and clinical significance of the TMPRSS2:ERG gene fusion in prostate cancer has been investigated with contradictory results. It is now common knowledge that significant variability in gene alterations exists according to ethnic background in various kinds of cancer. In this study, we evaluated gene fusions involving the ETS gene family in Japanese prostate cancer. Total RNA from 194 formalin-fixed and paraffin-embedded prostate cancer samples obtained by radical prostatectomy was subjected to reverse-transcriptase polymerase chain reaction to detect the common TMPRSS2:ERG T1-E4 and T1-E5 fusion transcripts and five other non-TMPRSS2:ERG fusion transcripts. We identified 54 TMPRSS2:ERG-positive cases (54/194, 28%) and two HNRPA2B1:ETV1-positive cases (2/194, 1%). The SLC45A3-ELK4 transcript, a fusion transcript without structural gene rearrangement, was detectable in five cases (5/194, 3%). The frequencies of both TMPRSS2:ERG- and non-TMPRSS2:ERG-positive cases were lower than those reported for European, North American or Brazilian patients. Internodular heterogeneity of TMPRSS2:ERG was observed in 5 out of 11 multifocal cases (45%); a frequency similar to that found in European and North American cases. We found a positive correlation between the TMPRSS2:ERG fusion and a Gleason score of ≤7 and patient age, but found no relationship with pT stage or plasma prostate-specific antigen concentration. To exclude the possibility that Japanese prostate cancer displays novel TMPRSS2:ERG transcript variants or has unique 5′ fusion partners for the ETS genes, we performed 5′ RACE using fresh-frozen prostate cancer samples. We identified only the normal 5′ cDNA ends for ERG, ETV1 and ETV5 in fusion-negative cases. Because we identified a relatively low frequency of TMPRSS2:ERG and other fusions, further evaluation is required before this promising molecular marker should be introduced into the management of Japanese prostate cancer patients.

Fluorescence in situ hybridization evaluation of c-myc and androgen receptor gene amplification and chromosomal anomalies in prostate cancer in Japanese patients

Oncogene amplification and chromosomal anomalies are found in many solid tumors and are often associated with aggressiveness of cancer. We evaluated the frequency and the association of c‐myc and androgen receptor (AR) gene amplification and gain of chromosome 8 or X in prostate cancer in Japanese patients.

Alterations of p16 and p14ARF genes and their 9p21 locus in oral squamous cell carcinoma.

The p16 gene encodes a 16-kDa cyclin kinase inhibitor, and the p14ARF gene a 14-kDa protein, which acts as a cell cycle regulator or tumor suppressor in human cancer cells. Both genes are mapped on chromosome 9p21. Previous studies have suggested that the p16 gene has important roles in head and neck squamous cell carcinoma. To clarify carcinogenesis in oral squamous cell carcinoma (OSCC), we examined 44 primary OSCCs for alterations of p16 and p14ARF mRNA expression, the methylation status of the p16 gene promoter, the loss of heterozygosity (LOH) at the 9p21 locus, and p16 and p14ARF gene mutations. Alterations of p16 and p14ARF mRNA expression were seen in 27 (61.4%) of 44 and 10 (22.7%) of 44 of OSCC samples, respectively. Methylation of the p16 gene promoter region was detected in 28 (63.6%) of 44 samples, and LOH at 9p21 locus was found in 30 (68.2%) of 44. p16 and p14ARF gene mutations were observed in 4 (9.0%) of 44 and 2 (4.5%) of 44 samples, respectively. Suspected homozygous deletion (HD) was seen in 9 (20.5%) of 44. All cases except one (97.7%) showed alterations in p16, p14ARF, and their locus. These data indicate that the status of p16 and p14ARF genes in OSCC is frequently influenced by methylation, gene mutation, and allelic deletions. Furthermore, these genes and their 9p21 locus have various roles in the pathogenesis of OSCC.

Detection of telomerase activity in prostate needle-biopsy samples

Telomerase in an enzyme ribonucleoprotein responsible for cell immortality and oncogenesis. Telomerase activity has been detected in most cancers, including prostate cancer. To verify whether the detection of telomerase in prostate needle biopsy samples could have diagnostic value, we blindly assayed telomerase activity in samples from patients who were clinically suspected of having prostate cancer.

DNA polymerase β gene mutations in human bladder cancer

We examined 24 human bladder cancer tissues for possible mutations in the entire coding region of the human DNA polymerase β gene using polymerase chain reaction analysis, single‐strand conformational polymorphism analysis of RNA, and sequence analysis. DNA polymerase β gene mutations were observed in four of the 24 cases (16.7%) and included three missense point mutations and a single base insertion. The single base insertion was also observed in our previous study of human prostate cancer, suggesting that this region may be a hot spot for mutation of the DNA polymerase β gene. No clinical or pathological association was found among the four cases that contained the mutation. Three of the four cases with DNA polymerase β gene mutation had mutations of the p16 or RB genes or loss of heterozygosity of the p53 and APC gene loci. The results of the study presented here suggest that DNA polymerase β gene mutations, in combination with mutations of tumor suppressor genes, may be involved in certain cases of human bladder cancer.

55 kDa nuclear matrix protein (nmt55) mRNA is expressed in human prostate cancer tissue and is associated with the androgen receptor

Most prostate cancer grows in a hormone‐dependent manner. Most patients, however, show hormone‐independent growth after several years of hormone therapy. The mechanism of hormone‐refractory prostate cancer remains unknown. It is important, therefore, to identify gene(s) related to prostate cancer that are up‐ or downregulated. We studied differences in gene expression in pairs of prostate cancer and normal prostate tissue utilizing the differential display method. Expression of the identified gene was examined by RT‐PCR and real time quantitative PCR (TaqMan‐PCR) using 26 pairs of human prostate cancer and normal tissues. We identified a specific upregulated gene encoding a 55 kDa nuclear matrix protein (nmt55) in human prostate cancer. nmt55 gene expression in human prostate cancer tissue was higher (20/26 cases) than that in normal prostate tissue. Moreover, the relationship between nmt55 and androgen receptor (AR) expression showed a positive correlation. In another experiment, transcriptional activity of the prostate specific antigen (PSA) promoter was upregulated by nmt55 in 293 cells. nmt55 showed high expression in prostate cancer compared to normal tissue and its expression showed a positive correlation with AR expression. The PSA promoter was activated by nmt55 expression. These results suggest the possibility that nmt55 expression is related to hormone‐dependency or ‐independence associated with the AR.

Primary testicular leiomyosarcoma.

Abstract  We report a case of primary testicular leiomyosarcoma. A 76‐year‐old man, who complained of left scrotal swelling for 6 months, underwent radical orchiectomy. Microscopic examination revealed intratesticular leiomyosarcoma. The patient received no adjuvant therapy and at 12 months after surgery, there had been no recurrence. Primary leiomyosarcoma of the testis is extremely rare; this is the 9th case recorded worldwide.

Usefulness of ultrasensitive prostate-specific antigen assay for early detection of biochemical failure after radical prostatectomy.

Background: In order to assess whether the prostate‐specific antigen (PSA) nadir obtained with an ultrasensitive PSA assay can be used as a prognostic indicator for patients undergoing radical prostatectomy, we investigated it retrospectively.

Neuroserpin (PI-12) is upregulated in high-grade prostate cancer and is associated with survival

We carried out Genechip analysis using prostate cancer and non‐malignant tissue to identify specific genes related to prostate cancer. We focused on neuroserpin (PI‐12), which has been identified as one of the genes with high expression in prostate cancer. We analyzed the relationship between its expression pattern and clinical characteristics. Prostate cancer and normal prostate tissue were analyzed by Affymetrix GeneChip technology. We carried out real‐time quantitative PCR on a total of 102 specimens: 45 of normal prostate, 45 of previously untreated prostate cancer (constituting 45 pairs of samples obtained at radical prostatectomy, with each pair dissected from the same prostate specimen) and 12 of recurrent hormone refractory prostate cancer (HRPC). Results showed that the neuroserpin gene was more highly expressed in prostate cancer than in normal prostate tissue. Neuroserpin expression in untreated prostate cancer was significantly higher than that in normal prostate. In HRPC it was significantly higher than that in untreated prostate cancer and normal prostate. In untreated prostate cancer, neuroserpin expression was significantly higher in high grade tumors such as poorly differentiated adenocarcinoma than in lower grade tumors such as well or moderately differentiated adenocarcinoma. Higher neuroserpin expression was associated with shorter recurrence‐free survival after radical prostatectomy, shorter recurrence‐free survival in HRPC patients and shorter overall survival in HRPC patients. The neuroserpin gene may be associated with the development, progression and aggressiveness of prostate cancer. Our present data suggests that higher neuroserpin expression may predict an unfavorable outcome after radical prostatectomy or hormone therapy.