Factors that influence the measurement of prostate cancer DNA ploidy and proliferation in paraffin embedded tissue evaluated by flow cytometry

PRMT3 regulates the progression of invasive micropapillary carcinoma of the breast

Invasive micropapillary carcinoma (IMPC) is a special histopathological subtype of breast cancer. Clinically, IMPC exhibits a higher incidence of lymphovascular invasion and lymph node metastasis compared with that of invasive ductal carcinoma (IDC), the most common type. However, the metabolic characteristics and related mechanisms underlying malignant IMPC biological behaviors are unknown. We performed large-scale targeted metabolomics analysis on resected tumors obtained from chemotherapy-naïve IMPC (n = 25) and IDC (n = 26) patients to investigate metabolic alterations, and we integrated mass spectrometry analysis, RNA sequencing, and ChIP-sequencing data to elucidate the potential molecular mechanisms. The metabolomics revealed distinct metabolic profiles between IMPC and IDC. For IMPC patients, the metabolomic profile was characterized by significantly high levels of arginine methylation marks, and protein arginine methyltransferase 3 (PRMT3) was identified as a critical regulator that catalyzed the formation of these arginine methylation marks. Notably, overexpression of PRMT3 was an independent risk factor for poor IMPC prognosis. Furthermore, we demonstrated that PRMT3 was a key regulator of breast cancer cell proliferation and metastasis both in vitro and in vivo, and treatment with a preclinical PRMT3 inhibitor decreased the xenograft tumorigenic capacity. Mechanistically, PRMT3 regulated the endoplasmic reticulum (ER) stress signaling pathway by facilitating histone H4 arginine 3 asymmetric dimethylation (H4R3me2a), which may endow breast cancer cells with great proliferative and metastatic capacity. Our findings highlight PRMT3 importance in regulating the malignant biological behavior of IMPC and suggest that small-molecule inhibitors of PRMT3 activity might be promising breast cancer treatments.

Characterization of the Tumor Microenvironment and the Biological Processes with a Role in Prostatic Tumorigenesis

Prostate intratumoral heterogeneity, driven by epithelial−mesenchymal plasticity, contributes to the limited treatment response, and it is therefore necessary to use the biomarkers to improve patient prognostic survival. We aimed to characterize the tumor microenvironment (T lymphocyte infiltration, intratumoral CD34, and KI-67 expressions) by immunohistochemistry methods and to study the biological mechanisms (cell cycle, cell proliferation by adhesion glycoproteins, cell apoptosis) involved in the evolution of the prostate tumor process by flow-cytometry techniques. Our results showed that proliferative activity (S-phase) revealed statistically significant lower values of prostate adenocarcinoma (PCa) and benign prostatic hyperplasia (BPH) reported at non-malignant adjacent cell samples (PCa 4.32 ± 4.91; BPH 2.35 ± 1.37 vs. C 10.23 ± 0.43, p < 0.01). Furthermore, 68% of BPH cases and 88% of patients with PCa had aneuploidy. Statistically increased values of cell proliferation (CD34+ CD61+) were observed in prostate adenocarcinoma and hyperplasia cases reported to non-malignant adjacent cell samples (PCa 28.79 ± 10.14; BPH 40.65 ± 11.88 vs. C 16.15 ± 2.58, p < 0.05). The CD42b+ cell population with a role in cell adhesion, and metastasis had a significantly increased value in PCa cases (38.39 ± 11.23) reported to controls (C 26.24 ± 0.62, p < 0.01). The intratumoral expression of CD34 showed a significantly increased pattern of PCa tissue samples reported to controls (PCa 26.12 ± 6.84 vs. C 1.50 ± 0.70, p < 0.01). Flow cytometric analysis of the cell cycle, apoptosis, and adhesion glycoproteins with a critical role in tumoral cell proliferation, T cell infiltrations, Ki-67, and CD 34 expressions by IHC methods are recommended as techniques for the efficient means of measurement for adenocarcinoma and hyperplasia prostate tissue samples and should be explored in the future.

Failure of Ploidy and Proliferative Fraction to Predict Long-Term Outcome After Prostatectomy

Background

Historically, ploidy and S phase percentage appeared to be promising predictors for prostate cancer recurrence. Lack of uniformity and consistency hampered their development. We evaluated ploidy and S phase for prostate cancer death in a cohort of patients with long-term follow-up.

Methods

We identified 127 patients that had ploidy and S phase determined at the time of their radical prostatectomy for prostate cancer. With 15 years of follow-up, we determined the risk of biochemical failure and risk of death from prostate cancer. We correlated the S phase and ploidy findings with standard pathology findings.

Results

A total of 107 (84%) had diploid and 20 (16%) had non-diploid cancers. The median S phase was 6.6%. There was no correlation of ploidy (P = 0.472) or S phase with preoperative PSA or Gleason score. On univariate analysis, EPE, margin positivity, seminal vesicle involvement, lymph node involvement, high Gleason score and PSA > 10 ng/mL were all predictive of biochemical failure. Ploidy and S phase were not. For prostate cancer death, only Gleason score was predictive.

Conclusions

With long-term follow-up in our cohort, Gleason score was predictive of prostate cancer death. Ploidy and S phase were not predictive for biochemical failure or prostate cancer mortality.

Revisiting tumour aneuploidy - the place of ploidy assessment in the molecular era

Chromosome instability (CIN) is gaining increasing interest as a central process in cancer. CIN, either past or present, is indicated whenever tumour cells harbour an abnormal quantity of DNA, termed 'aneuploidy'. At present, the most widely used approach to detecting aneuploidy is DNA cytometry - a well-known research assay that involves staining of DNA in the nuclei of cells from a tissue sample, followed by analysis using quantitative flow cytometry or microscopic imaging. Aneuploidy in cancer tissue has been implicated as a predictor of a poor prognosis. In this Review, we have explored this hypothesis by surveying the current landscape of peer-reviewed research in which DNA cytometry has been applied in studies with disease-appropriate clinical follow up. This area of research is broad, however, and we restricted our survey to results published since 2000 relating to seven common epithelial cancers (those of the breast; endometrium, ovary, and uterine cervix; oesophagus; colon and rectum; lung; prostate; and bladder). We placed particular emphasis on results from multivariate analyses to pinpoint situations in which the prognostic value of aneuploidy as a biomarker is strong compared with that of existing indicators, such as clinical stage, histological grade, and specific molecular markers. We summarize the implications of our findings for the prognostic use of ploidy analysis in the clinic and for the theoretical understanding of the role of CIN in carcinogenesis.

The use of FNA samples for whole-exome sequencing and detection of somatic mutations in breast cancer surgical specimens

BACKGROUND

The availability of suitable biospecimens is critical to the success of advanced genomic analyses. The objective of this study was to assess the sensitivity of fine-needle aspiration (FNA) compared with gross surgical sampling (GSS) from surgical specimens for the detection of somatic mutations in breast cancer using whole-exome sequencing (WES).

METHODS

DNA was extracted from paired GSS tissues and FNA samples of surgically resected breast cancer from 12 patients and was used for WES. Sanger sequencing was performed to validate selected somatic mutations. Tumor purity was calculated for each sample using sequencing data.

RESULTS

There was no difference in the total amount of DNA extracted from GSS tissues and FNA samples. WES was successfully performed for all 12 pairs of samples. The median number of somatic mutations identified in individual samples was higher in FNA samples than in GSS tissues (39.5 vs 18.5; P = .036). The somatic mutation profiles from both sampling methods were well correlated for samples that had GSS tissues with high tumor content, as indicated by hematoxylin and eosin staining. Nineteen mutations that were identified exclusively in FNA samples were subjected to Sanger sequencing, and 13 of those mutations (68.4%) were validated. The mean estimated tumor purity was higher in FNA samples than in GSS tissues (55.87% vs 25.76%), and FNA samples were estimated to have a consistently higher proportion of malignant cells.

CONCLUSIONS

The current results suggest that FNA is feasible for the collection of tumor samples sufficient for WES analysis and that the higher purity obtained using this method may make it more reliable for genomic studies.

TMPRSS2-ERG gene fusion is not associated with outcome in patients treated by prostatectomy

A significant number of prostate cancers have been shown to have recurrent chromosomal rearrangements resulting in the fusion of the androgen-regulated TMPRSS2 promoter to a member of the ETS transcription factor family, most commonly ERG. This results in ERG overexpression, which may have a direct causal role in prostate tumorigenesis or progression. However, the clinical significance of the rearrangement is unclear, and in particular, relationship to outcome has been inconsistent in recent reports. We analyzed TMPRSS2-ERG gene rearrangement status by fluorescence in situ hybridization in 521 cases of clinically localized surgically treated prostate cancer with 95 months of median follow-up and also in 40 unmatched metastases. Forty-two percent of primary tumors and 40% of metastases had rearrangements. Eleven percent had copy number increase (CNI) of the TMPRRS2-ERG region. Rearrangement alone was associated with lower grade, but not with stage, biochemical recurrence, metastases, or death. CNI with and without rearrangement was associated with high grade and advanced stage. Further, a subgroup of cancers with CNI and rearrangement by deletion, with two or more copies of the deleted locus, tended to be more clinically aggressive. DNA index assessment revealed that the majority of tumors with CNI of TMPRSS2-ERG had generalized aneuploidy/tetraploidy in contrast to tumors without TMPRSS2-ERG CNI, which were predominantly diploid. We therefore conclude that translocation of TMPRSS2-ERG is not associated with outcome, and the aggressive clinical features associated with CNI of chromosome 21 reflect generalized aneuploidy and are not due to CNI specifically of rearranged TMPRSS2-ERG.

Treatment of Prostate Cancer Local Recurrence After Radical Retropubic Prostatectomy with 17-Gauge Interstitial Transperineal Cryoablation: Initial Experience

OBJECTIVES

Interstitial transperineal cryoablation with 17-gauge cryoprobes is an accepted treatment modality for localized prostate cancer. The effectiveness of cryoablation in the treatment of local prostate cancer recurrence after radical retropubic prostatectomy (RRP) is unknown.

METHODS

We reviewed the outcome of cryoablative treatment in 15 patients for biopsy-proven locally recurrent prostate cancer after RRP. The follow-up data included prostate-specific antigen (PSA) level, imaging findings, side effects, and an assessment of voiding habits.

RESULTS

The mean follow-up time for the entire group was 20 months (range 4 to 32). Of the 15 patients, 6 (40%) had sustained declines in the PSA level (cryoablation success group) and 9 (60%) had disease progression (cryoablation failure group), defined as a PSA increase greater than 0.1 ng/mL from the PSA nadir, or the addition of external beam radiotherapy or androgen deprivation therapy. The pre-RRP PSA level and pre-cryoablation PSA level were similar for both groups. The pre-RRP biopsy Gleason scores (P = 0.03), RRP Gleason scores (P = 0.03), and lesion size on magnetic resonance imaging (P = 0.001) were lower in the success group than in the failure group. All patients who were recurrence free after cryotherapy had a biopsy and Gleason score of 6 or less. Of the 15 patients, 3 (20%) developed worsening of post-RRP incontinence.

CONCLUSIONS

Our preliminary results suggest that salvage cryoablation can be an effective and safe treatment modality and a possible alternative to external beam radiotherapy for targeted control of confirmed local recurrences after RRP, especially in those with favorable biopsy or pathologic Gleason scores before cryotherapy. Larger cohorts and longer follow-up are needed to assess the viability of this treatment.

Bub1 up-regulation and hyperphosphorylation promote malignant transformation in SV40 tag-induced transgenic mouse models

Rodents do not naturally develop prostate cancer. Currently, most widely used genetically engineered mouse prostate cancer models use SV40 T/tag oncogene. To understand the mechanism underlying prostate cancer development in transgenic and knock-in SV40 Tag mouse models, we did cDNA microarray analyses, comparing gene expression profiles of prostate cancer tissues from early-, late-, and advance-stage androgen-independent prostate cancers. Of the 67 genes that were up-regulated by > or = 10-fold, 40 are known to be required for chromosome stability. In particular, the spindle checkpoint component Bub1 was persistently up-regulated from early to advanced androgen-independent prostate cancer lesions. Significantly, Bub1, which is required for accurate chromosome segregation during mitosis, has recently been reported to bind SV40 Tag. Consistent with a spindle checkpoint defect, flow cytometry experiments indicate that advanced androgen-independent prostate cancer tumors exhibit aneuploidy, along with up-regulation of levels of both Bub1 mRNA and Bub1 protein or hyperphosphorylation. Importantly, up-regulation and hyperphosphorylation of Bub1 were also observed in established human prostate cancer cell lines and in clinical studies. Furthermore, analysis of human prostate cancer lines showed impaired spindle checkpoint function and endoreduplication following exposure to spindle toxins. Small interfering RNA-mediated repression of Bub1 in the human prostate cancer line PC-3 restrained cell proliferation, an effect mimicked by inhibition of mitogen-activated protein kinase, an upstream activator of Bub1. Thus, by perturbing Bub1 function, our observations suggest a new mechanism whereby the SV40 Tag oncoprotein promotes chromosomal instability and aneuploidy in transgenic mouse prostate cancer models. Whereas the exact details of this mechanism remain unclear, our novel findings raise the possibility of exploiting Bub1 as a new therapeutic target in the treatment of prostate cancer, the most common cancer in adult men in North America.

Impact of Familial and Hereditary Prostate Cancer on Cancer Specific Survival After Radical Retropubic Prostatectomy

PURPOSE

Men with a family history of prostate cancer are at higher risk for prostate cancer. There are conflicting data regarding the impact of hereditary forms of prostate cancer on long-term outcomes after radical prostatectomy. We examined the impact of familial and hereditary prostate cancer treatment in the prostate specific antigen era.

MATERIALS AND METHODS

Patients who underwent radical prostatectomy for prostate cancer from 1987 to 1997 were surveyed (3,560 responders) to determine the family history of prostate cancer. Patients were categorized as having familial prostate cancer if they had at least 1 first-degree relative with prostate cancer. Hereditary prostate cancer was defined as nuclear families with 3 cases of prostate cancer, families with prostate cancer in each of 3 generations and families with 2 men diagnosed before age 55 years. Sporadic prostate cancer was defined as patients with no family history. Clinical and pathological features, and long-term outcome measures, including biochemical recurrence-free, systemic progression-free and cancer specific survival, were compared among patients with familial, hereditary and sporadic prostate cancer.

RESULTS

A total of 865 and 133 patients were categorized as having familial prostate cancer and hereditary prostate cancer, respectively. Preoperatively prostate specific antigen was higher in patients with hereditary prostate cancer than in the other 2 groups (p = 0.04). Ten-year biochemical progression-free, systemic progression-free and cancer specific survival were equivalent.

CONCLUSIONS

Except for preoperative prostate specific antigen, clinicopathological features and long-term oncological outcomes are equivalent after radical prostatectomy in patients with familial, hereditary and sporadic prostate cancer.

Histopathological characteristics of a novel knock-in mouse prostate cancer model

Prostate cancer is relatively unique to man. There is no naturally occurring prostate cancer in the mouse. Pre-clinical studies involve the establishment of a genetically engineered mouse prostate cancer model with features close to those of the human situation. A new knock-in mouse adenocarcinoma prostate (KIMAP) model was established, which showed close-to-human kinetics of tumor development. In order to determine if the similar kinetics is associated with heterogeneous tumor architecture similar to the human situation, we utilized a new mouse histological grading system (Gleason analogous grading system) similar to the Gleason human grading system and flow cytometry DNA analysis to measure and compare the adenocarcinoma of the KIMAP model with human prostate cancer. Sixty KIMAP prostate cancer samples from 60 mice were measured and compared with human prostate cancer. Flow cytometry DNA analysis was performed on malignant prostate tissues obtained from KIMAP models. Mice with prostate cancer from KIMAP models showed a 53.3% compound histological score rate, which was close to the human clinical average (50%) and showed a significant correlation with age (P = 0.001). Flow cytometry analyses demonstrated that most KIMAP tumor tissues were diploid, analogous to the human situation. The similarities of the KIMAP mouse model with tumors of the human prostate suggest the use of this experimental model to complement studies of human prostate cancer.

Impact of Patient Age at Treatment on Outcome Following Radical Retropubic Prostatectomy for Prostate Cancer

PURPOSE

Historically young patients with prostate cancer have been found to have poorer outcomes. Recent studies suggest favorable pathological findings and improved survival in younger patients undergoing RRP. We assessed age at treatment as a predictor of post-RRP survival.

MATERIALS AND METHODS

We identified 5,509 patients treated with RRP for prostate cancer at our institution between 1987 and 1995. Age at treatment was classified into categories of younger than 55, 55 to 59, 60 to 64, 65 to 69 and 70 years or older. CSS, sPFS and biochemical PFS were estimated by the Kaplan-Meier method and analyzed using Cox proportional hazard models.

RESULTS

Younger patients had lower preoperative prostate specific antigen, and tumor grade and stage. CSS, sPFS and biochemical PFS were similar across age groups but overall survival decreased with older age at treatment. After multivariate adjustment the risk of cancer death was lower in patients 70 years or older (RR 0.53, 95% CI 0.30 to 0.90), while the risk of progression was lower in all age groups compared to that in men younger than 55 years (RR 0.57 to 0.62). On stratified subset analysis sPFS was progressively worse with younger age in patients with high risk pathological findings. However, the addition of age to multivariate models incorporating preoperative prostate specific antigen, pathological features and adjuvant therapy failed to improve their predictive value for CSS and sPFS.

CONCLUSIONS

Despite more favorable clinicopathological features younger patients undergoing RRP for prostate cancer have survival similar to that of older counterparts. Given the greater proportionate impact of prostate cancer on survival, it is particularly important to pursue aggressive treatment in younger patients.

Application of Gleason analogous grading system and flow cytometry DNA analysis in a novel knock-in mouse prostate cancer model

OBJECTIVE

A new knock-in mouse adenocarcinoma prostate model (KIMAP) was established, which showed a close to human kinetics of tumour development. This study used a new mouse histological grading system similar to the human Gleason grading system and flow cytometry DNA analysis to measure and compare the new KIMAP model with human CaP and transgenic mouse adenocarcinoma prostate (TGMAP) model.

METHODS

According to heterogeneity of the clinical standard for prostate cancer diagnosis, a close to human mouse standard for histological grading and scoring system, Gleason analogous grading system, was established in this study. Sixty KIMAP and 48 TGMAP prostate cancer samples were measured and compared with human CaP. Flow cytometry DNA analysis was performed on malignant prostate tissues obtained from both TGMAP and KIMAP models.

RESULTS

Mice with CaP from KIMAP (n = 60) and TGMAP (n = 48) models showed a different distribution of histological scores (p = 0.000). KIMAP mice showed higher percentage (53.3%) of compound histological score rate than TGMAP (25%), but closer to the human clinical average (50%), which showed significant correlation with age (p = 0.001), while TGMAP mice showed unbalanced and random score distribution in all age groups. Flow cytometry analyses showed that most tumour tissues in KIMAP were diploid, analogous to the human condition, while all the TGMAP mice showed aneuploid tumours.

CONCLUSIONS

Results of this study further show that KIMAP, a new generation of murine prostate cancer model, could be used as a supplementary model in addition to the currently widely used transgenic models.

A prospective comparison of digital image analysis and routine cytology for the identification of malignancy in biliary tract strictures

BACKGROUND & AIMS

Digital image analysis (DIA) allows quantification of nuclear DNA content and may help distinguish benign and malignant strictures of the biliary tract.

METHODS

One hundred ten consecutive patients undergoing endoscopic retrograde cholangiography for suspicious biliary tract strictures were enrolled in a prospective study comparing the accuracy of DIA and routine cytology (RC). Standard brush cytology sampling was performed twice by using 2 cytology brushes per patient. Both brushes were fixed in a single-specimen vial. Each specimen was formed into 1 pellet, and the sample was equally divided for evaluation by DIA and RC. DNA histograms were generated for ploidy analysis. The DIA criterion for malignancy was demonstration of aneuploidy.

RESULTS

Two patients had inadequate samples obtained for DIA analysis, 7 benign patients were excluded because of inadequate follow-up of less than 75 days, and 1 patient was lost to follow-up to clarify malignant versus benign disease. Of the remaining 100 patients, 56 strictures were malignant and 44 were benign. The sensitivities of DIA and RC were 39.3% and 17.9%, respectively (P = 0.014). The specificities of DIA and RC were 77.3% and 97.7%, respectively (P = 0.003). The accuracy of DIA (56.0%) was equivalent to RC (53.0%).

CONCLUSIONS

DIA is a valuable adjunct to RC for detecting malignant strictures of the biliary tract.

Human prostate cancer risk factors

Prostate cancer has the highest prevalence of any nonskin cancer in the human body, with similar likelihood of neoplastic foci found within the prostates of men around the world regardless of diet, occupation, lifestyle, or other factors. Essentially all men with circulating androgens will develop microscopic prostate cancer if they live long enough. This review is a contemporary and comprehensive, literature-based analysis of the putative risk factors for human prostate cancer, and the results were presented at a multidisciplinary consensus conference held in Crystal City, Virginia, in the fall of 2002. The objectives were to evaluate known environmental factors and mechanisms of prostatic carcinogenesis and to identify existing data gaps and future research needs. The review is divided into four sections, including 1) epidemiology (endogenous factors [family history, hormones, race, aging and oxidative stress] and exogenous factors [diet, environmental agents, occupation and other factors, including lifestyle factors]); 2) animal and cell culture models for prediction of human risk (rodent models, transgenic models, mouse reconstitution models, severe combined immunodeficiency syndrome mouse models, canine models, xenograft models, and cell culture models); 3) biomarkers in prostate cancer, most of which have been tested only as predictive factors for patient outcome after treatment rather than as risk factors; and 4) genotoxic and nongenotoxic mechanisms of carcinogenesis. The authors conclude that most of the data regarding risk relies, of necessity, on epidemiologic studies, but animal and cell culture models offer promise in confirming some important findings. The current understanding of biomarkers of disease and risk factors is limited. An understanding of the risk factors for prostate cancer has practical importance for public health research and policy, genetic and nutritional education and chemoprevention, and prevention strategies.

Microsatellite instability in hereditary and sporadic breast cancers

Sporadic cancers and familial breast cancers are characterized by an increase in genetic instability. Little is known about whether mismatch repair defects accompany this genetic instability. We investigated invasive and/or in situ breast cancers from 30 women with deleterious BRCA1/2 mutations and unclassified variant BRCA1/2 alterations. Forty cases of sporadic breast cancers were also investigated, including 7 medullary carcinomas. Malignant and benign lesions were examined from all cases to better understand tumor progression. Automated immunohistochemistry, with antibodies directed against hMLH1 and hMSH2, was used to screen cases for possible mismatch repair defects. When loss of expression was noted, DNA ploidy was performed by cytomorphometry. DNA, after laser microdissection, was extracted from a majority of familial cases and their corresponding controls, and microsatellite instability analysis was performed. None of the familial or sporadic cases had loss of hMSH2 expression. All but one lesion, a DCIS arising in a deleterious BRCA2 mutation carrier, had loss of hMLH1 expression and a tetraploid profile by image cytomorphometry. There was no MSI in any explored lesions (n = 34), as determined by molecular analysis, including the DCIS with loss of hMLH1 expression. We conclude that DNA mismatch repair defects involving hMLH1 and hMSH2 underexpression are extremely rare events in sporadic and familial breast cancer. Mismatch repair gene mutations may be secondary random events in breast cancer progression.