Randomized, double-blinded phase II study of ketoconazole (keto), hydrocortisone (HC), and anti-PSMA antibody J591 labeled with 177Lu or 111In in patients (pts) with high-risk non-metastatic (met) castration-resistant prostate cancer (M0 CRPC)

LBA21

Background: Up to 1/3 of pts develop biochemical relapse following primary therapy. Many are not cured with salvage local therapy, likely because of undetectable distant disease. PSMA is expressed on most PC and can be targeted by radiolabeled J591. 177Lu is a predominantly β-emitting radionuclide and also has γ emission which allows imaging. 111In is predominantly a γ emitter, also with some auger emission for therapy. Hormonal therapy is effective and may increase PSMA expression and radiosensitize. In this DOD-funded study initiated in the pre-PSMA PET and AR signaling inhibitor era, we hypothesized that 177Lu prolongs 18-month (mo) met-free survival (MFS) more than 111In in pts with high risk, M0 CRPC when targeting PSMA via J591 in combo with keto and HC. Methods: Pts with high-risk M0 CRPC defined by PSA DT < 8 mo and/or absolute PSA > 20 ng/mL and serum testosterone < 50 ng/mL with no evidence of metastatic disease on CT/MRI and bone scan were eligible. Treatment included a minimum 4 week lead-in with keto 400 mg TID and HC 20 mg AM, 10 mg PM (both of which could be continued until unacceptable toxicity or development of mets) and a single infusion of J591 with 2:1 randomization to 177Lu (70 mCi/m2) or 111In (5 mCi) in double-blinded fashion. The final version of the protocol was designed to randomize 55 pts for 80% power to detect a difference in 18-mo MFS with one-sided alpha of 10%. Secondary endpoints include median MFS, PSA response, overall survival, and toxicity. Results: 55 pts with median age 68 (range 52 - 88), 75% prostatectomy, 23% primary radiation, 2% primary ADT; 19% local salvage therapy. Median PSA doubling time 3 mo (range 0.87 – 7.85), median baseline PSA 8.0 (range 1-78). In intent to treat analysis (5 without imaging and 4 lost to follow up by 18 mo), 50% developed mets by 18 mo with 177Lu vs 76% with 111In (p=0.066). Median MFS was 23.8 mo vs 20.8 mo, and biochemical PFS was 18.67 vs 8.87 mo, favoring 177Lu in analyses censoring start of new treatment. Confirmed >50% PSA decline occurred in 82% with 177Lu and 71% with 111In. Grade >3 heme AEs were more common with 177Lu vs 111In, including neutropenia (57% vs 11%, with 1 febrile neutropenia) and thrombocytopenia (77% vs 11%, with 25% vs 6% platelet transfusions), whereas Gr >3 non-heme AEs were less common with 177Lu vs 111In, including abdominal pain (0 vs 11%), ALT increase (3.3% vs 22%), and diarrhea (0 vs 22%). Conclusions: Anti-PSMA mAb J591 with keto/HC when radiolabeled with 177Lu leads to improved 18-month met-free survival vs 111In. Most pts had significant PSA decline with either version of radiolabeled J591 with keto/HC. Hematologic toxicity is more common with 177Lu. This supports the development of anti-PSMA radioimmunotherapy for low volume advanced PC, though the optimal radionuclide and targeting agent is unknown. Clinical trial information: NCT00859781 .

STAG2 as a prognostic biomarker in low-grade non-muscle invasive bladder cancer

OBJECTIVE

Improvements to bladder cancer risk stratification guidelines are needed to better tailor post-operative surveillance and adjuvant therapy to individual patients. We previously identified STAG2 as a commonly mutated tumor suppressor gene in bladder cancer and an independent predictor of progression in NMIBC. Here we test the value of combining STAG2 immunostaining with other risk stratification biomarkers in NMIBC, and as an individual biomarker in MIBC.

MATERIALS AND METHODS

STAG2 immunohistochemistry was performed on a progressor-enriched cohort of tumors from 297 patients with NMIBC, and on tumors from 406 patients with MIBC from Aarhus University Hospital in Denmark. Survival analysis was performed using Kaplan-Meier survival analysis, the log rank test, and Cox proportional hazards models.

RESULTS

STAG2-negative low-grade NMIBC tumors were 2.5 times less likely to progress to muscle invasion than STAG2-positive low-grade NMIBC tumors (Log-rank test, P = 0.008). In a composite group of patients with AUA intermediate and high-risk NMIBC tumors, STAG2-negative tumors were less likely to progress (Log-rank test, P = 0.02). In contrast to NMIBC, we show that STAG2 is not useful as a prognostic biomarker in MIBC.

CONCLUSIONS

STAG2 immunostaining can be used to subdivide low-grade NMIBC tumors into two groups with substantially different risks of disease progression. Furthermore, STAG2 immunostaining may be useful to enhance NMIBC risk stratification guidelines, though larger cohorts are needed to solidify this conclusion in individual risk groups. STAG2 is not useful as a biomarker in MIBC. Further study of the use of STAG2 immunostaining as a biomarker for predicting the clinical behavior in NMIBC is warranted.

Randomized Double-Blind Phase II Study of Maintenance Pembrolizumab Versus Placebo After First-Line Chemotherapy in Patients With Metastatic Urothelial Cancer

PURPOSE

Platinum-based chemotherapy for first-line treatment of metastatic urothelial cancer is typically administered for a fixed duration followed by observation until progression. "Switch maintenance" therapy with PD-1 blockade at the time of chemotherapy cessation may be attractive for mechanistic and pragmatic reasons.

PATIENTS AND METHODS

Patients with metastatic urothelial cancer achieving at least stable disease on first-line platinum-based chemotherapy were enrolled. Patients were randomly assigned double-blind 1:1 to switch maintenance pembrolizumab 200 mg intravenously once every 3 weeks versus placebo for up to 24 months. Patients with disease progression on placebo could cross over to pembrolizumab. The primary objective was to determine the progression-free survival. Secondary objectives included determining overall survival as well as treatment outcomes according to PD-L1 combined positive score (CPS).

RESULTS

Between December 2015 and November 2018, 108 patients were randomly assigned to pembrolizumab (n = 55) or placebo (n = 53). The objective response rate was 23% with pembrolizumab and 10% with placebo. Treatment-emergent grade 3-4 adverse events occurred in 59% receiving pembrolizumab and 38% of patients receiving placebo. Progression-free survival was significantly longer with maintenance pembrolizumab versus placebo (5.4 months [95% CI, 3.1 to 7.3 months] v 3.0 months [95% CI; 2.7 to 5.5 months]; hazard ratio, 0.65; log-rank P = .04; maximum efficiency robust test P = .039). Median overall survival was 22 months (95% CI, 12.9 months to not reached) with pembrolizumab and 18.7 months (95% CI, 11.4 months to not reached) with placebo. There was no significant interaction between PD-L1 CPS ≥ 10 and treatment arm for progression-free survival or overall survival.

CONCLUSION

Switch maintenance pembrolizumab leads to additional objective responses in patients achieving at least stable disease with first-line platinum-based chemotherapy and prolongs progression-free survival in patients with metastatic urothelial cancer.

Randomized double-blind phase II study of maintenance pembrolizumab versus placebo after first-line chemotherapy in patients (pts) with metastatic urothelial cancer (mUC): HCRN GU14-182

4504

Background: Platinum-based chemotherapy for 1st-line treatment of pts with metastatic urothelial cancer (mUC) is typically administered for a fixed duration followed by observation until recurrence. PD-1 blockade with pembro improves survival of pts with mUC progressing despite platinum-based chemotherapy. We explored the potential benefit of earlier use of PD-1 blockade using a "switch maintenance" approach. Methods: Pts with mUC achieving at least stable disease after up to 8 cycles of 1st-line platinum-based chemotherapy were enrolled. Pts were randomized 1:1 to pembro 200 mg IV q3 weeks versus placebo for up to 24 months; pts progressing on placebo could cross over to pembro. Randomization was stratified based on pre-chemotherapy visceral metastases (Y/N) and response to 1st-line chemotherapy (CR/PR vs. SD). The primary objective was to determine the progression-free survival (PFS) as per irRECIST among pts treated with pembro versus placebo. Results: Between 12/2015 and 11/2018, 107 pts were randomized to placebo (n=52) versus pembro (n=55). The baseline pt characteristics are shown in the Table. Pts randomized to placebo and pembro received a median of 6 and 8 cycles, respectively. Excluding patients with baseline CRs, the objective response rate was 12% (5/42) on placebo and 22% (10/46) on pembro. Grade 3-4 treatment emergent adverse events occurred in 48% of pts on placebo and 56% on pembro. At a median follow-up of 14.7 months, 41 pts have died and 26/52 pts randomized to placebo have crossed over to pembro. PFS was significantly longer in patients randomized to pembro vs. placebo (Maximum Efficiency Robust Test p=0.036; log-rank p = 0.038). The 18-month restricted mean progression-free survival time was 5.6 months with placebo and 8.2 months with pembro (p=0.023). Conclusions: Switch maintenance pembro may “deepen” responses achieved with 1st-line chemotherapy. Switch maintenance pembro prolongs PFS in pts with mUC completing 1st-line platinum-based chemotherapy. Clinical trial information: NCT02500121. [Table: see text]

STAG2 Is a Biomarker for Prediction of Recurrence and Progression in Papillary Non-Muscle-Invasive Bladder Cancer

Purpose: Most bladder cancers are early-stage tumors known as papillary non-muscle-invasive bladder cancer (NMIBC). After resection, up to 70% of NMIBCs recur locally, and up to 20% of these recurrences progress to muscle invasion. There is an unmet need for additional biomarkers for stratifying tumors based on their risk of recurrence and progression. We previously identified STAG2 as among the most commonly mutated genes in NMIBC and provided initial evidence in a pilot cohort that STAG2-mutant tumors recurred less frequently than STAG2 wild-type tumors. Here, we report a STAG2 biomarker validation study using two independent cohorts of clinically annotated papillary NMIBC tumors from the United States and Europe.Experimental Design: The value of STAG2 immunostaining for prediction of recurrence was initially evaluated in a cohort of 82 patients with papillary NMIBC ("Georgetown cohort"). Next, the value of STAG2 immunostaining for prediction of progression to muscle invasion was evaluated in a progressor-enriched cohort of 253 patients with papillary NMIBC ("Aarhus cohort").Results: In the Georgetown cohort, 52% of NMIBC tumors with intact STAG2 expression recurred, whereas 25% of STAG2-deficient tumors recurred (P = 0.02). Multivariable analysis identified intact STAG2 expression as an independent predictor of recurrence (HR = 2.4; P = 0.05). In the progressor-enriched Aarhus cohort, 38% of tumors with intact STAG2 expression progressed within 5 years, versus 16% of STAG2-deficient tumors (P < 0.01). Multivariable analysis identified intact STAG2 expression as an independent predictor of progression (HR = 1.86; P = 0.05).Conclusions: STAG2 IHC is a simple, binary, new assay for risk stratification in papillary NMIBC. Clin Cancer Res; 24(17); 4145-53. ©2018 AACR.

Physicians' Perceptions of Factors Influencing the Treatment Decision-making Process for Men With Low-risk Prostate Cancer

OBJECTIVE

To assess physicians' attitudes regarding multiple factors that may influence recommendations for active surveillance (AS) vs active treatment (AT) given the central role physicians play in the treatment decision-making process.

MATERIALS AND METHODS

We conducted semistructured interviews to assess factors that physicians consider important when recommending AS vs AT, as well as physicians' perceptions of what their patients consider important in the decision. Participants included urologists (N = 11), radiation oncologists (N = 12), and primary care physicians (N = 10) from both integrated and fee-for-service healthcare settings.

RESULTS

Across the specialties, quantitative data indicated that most physicians reported that their recommendations for AS were influenced by patients' older age, willingness and ability to follow a surveillance protocol, anxiety, comorbidities, life expectancy, and treatment preferences. Qualitative findings highlighted physicians' concerns about malpractice lawsuits, given the possibility of disease progression. Additionally, most physicians noted the role of the healthcare setting, suggesting that financial incentives may be associated with AT recommendations in fee-for-service settings. Finally, most physicians reported spouse or family opposition to AS due to their own anxiety or lack of understanding of AS.

CONCLUSION

We found that patient and physician preferences, healthcare setting, and family or spouse factors influence physicians' treatment recommendations for men with low-risk PCa. These were consistent themes across physician subspecialties in both an Health Maintenance Organization and in fee-for-service settings.

Utilization and predictors of expectant management among elderly men with low-and intermediate-risk localized prostate cancer in U.S. urological practice

INTRODUCTION

Expectant management (EM) reduces overtreatment in low-risk but not intermediate-risk localized prostate cancer (PCa). We assessed the use and predictors of EM to understand its uptake in U.S. practice.

METHODS

Using the U.S. SEER-Medicare database, we conducted a retrospective cohort study of men 66 years and older diagnosed with low-risk (N=25,506) or intermediate-risk (N=25,597) localized PCa between 2004 - 2011 and followed through December 31, 2012. We defined EM as no definitive therapy (DT) and at least one prostate-specific antigen (PSA) test or re-biopsy 4 - 12 months post diagnosis; or receiving DT after PSA testing or re-biopsy 7 - 12 months after diagnosis. We performed separate analyses for low-risk and intermediate-risk groups using multiple logistic regressions.

RESULTS

For men diagnosed with PCa in 2004-2011, EM increased from 22% to 43% in the low-risk group and from 15% to 18% in the intermediate-risk group. In the low-risk group, EM increased with patients' age (adjusted odds ratio [aOR] = 1.26 for 71-75 years; 2.21 for 76-80 years; 6.33 for older then 80, p<0.0001, compared to 66-70 years). EM uptake was higher among men with comorbidities (aOR=1.29), and residing in the Pacific region (aOR=0.56, compared to the East Coast).

CONCLUSIONS

In U.S. practice, the utilization of EM steadily increased in low-risk PCa and remained low in the intermediate-risk group over time. While patients with advanced age or comorbidities were more likely to receive EM, its use varied substantially by geographic region. Our findings bring attention to the presence of multiple barriers for EM implementation.

NKT-associated hedgehog and osteopontin drive fibrogenesis in non-alcoholic fatty liver disease

OBJECTIVE

Immune responses are important in dictating non-alcoholic steatohepatitis (NASH) outcome. We previously reported that upregulation of hedgehog (Hh) and osteopontin (OPN) occurs in NASH, that Hh-regulated accumulation of natural killer T (NKT) cells promotes hepatic stellate cell (HSC) activation, and that cirrhotic livers harbour large numbers of NKT cells.

DESIGN

The hypothesis that activated NKT cells drive fibrogenesis during NASH was evaluated by assessing if NKT depletion protects against NASH fibrosis; identifying the NKT-associated fibrogenic factors; and correlating plasma levels of the NKT cell-associated factor OPN with fibrosis severity in mice and humans.

RESULTS

When fed methionine-choline-deficient (MCD) diets for 8 weeks, wild type (WT) mice exhibited Hh pathway activation, enhanced OPN expression, and NASH-fibrosis. Ja18-/- and CD1d-/- mice which lack NKT cells had significantly attenuated Hh and OPN expression and dramatically less fibrosis. Liver mononuclear cells (LMNCs) from MCD diet fed WT mice contained activated NKT cells, generated Hh and OPN, and stimulated HSCs to become myofibroblasts; neutralising these factors abrogated the fibrogenic actions of WT LMNCs. LMNCs from NKT-cell-deficient mice were deficient in fibrogenic factors, failing to activate collagen gene expression in HSCs. Human NASH livers with advanced fibrosis contained more OPN and Hh protein than those with early fibrosis. Plasma levels of OPN mirrored hepatic OPN expression and correlated with fibrosis severity.

CONCLUSION

Hepatic NKT cells drive production of OPN and Hh ligands that promote fibrogenesis during NASH. Associated increases in plasma levels of OPN may provide a biomarker of NASH fibrosis.

External validation of prognostic models for overall survival (OS) in patients (pts) with advanced cancer (UC) treated with cisplatin-based chemotherapy

4592

Background: The most commonly used model predicting OS for UC pts treated with cisplatin-based chemotherapy is based on 2-variables (visceral metastases and performance status), developed at MSKCC in 1999, and validated in a phase III study (DeSantis JCO 2011). A prognostic model of OS for advanced UC pts based on 4 variables (visceral metastases, albumin, performance status, and hemoglobin) was developed using 308 pts from MSKCC (ASCO 2007 abstr 5055). We report the discriminative ability of the 4- and 2- variable models for advanced UC pts using an independent dataset from CALGB 90102. Methods: The analysis was performed using an external multi-institutional dataset from CALGB 90102. The primary measurement of predictive discrimination was Harrell’s c-index which was computed with 95% confidence interval (CI). To assess whether there was a statistically significant difference in discrimination between the two models, the U statistic was used to test whether the predictions of the 4-variable model in all possible pairs were more concordant with actual observations than the 2-variable model in the same pairs. Results: CALGB 90102 included 74 UC pts (58 males, 16 females), median age 64 years, treated with cisplatin, gemcitabine and gefitinib, enrolled from 7/02 to 4/05 with a median follow-up of 72.5 months. Visceral metastases were present in 64% (bone, 18%, liver, 31%, lung, 43%), median KPS 90%. The MSKCC 2-variable risk group distribution was 30% =0, 65%= 1 and 5%=2. The median OS =12.7 months (95% CI=10.4-20.5) with 68 deaths observed. When applied to the CALGB cohort, the predictive accuracy for the 4- and 2-variable models were 0.63 (95 CI= 0.56- 0.69) and 0.58 (95% CI= 0.52-0.65), respectively. There was a statistically significant difference in discrimination between the two models (p =0.019), with superiority of the 4-variable model compared to the 2-variable model. Conclusions: A 4-variable prognostic nomogram for survival in pts with advanced UC was superior to a 2-variable risk-group model. The 4-variable prognostic model may replace the widely used 2-variable model and can be used in the design and conduct of future phase II and III trials in advanced UC.

Efficacy of peripheral androgen blockade in prostate cancer patients with biochemical failure after definitive local therapy: results of Cancer and Leukemia Group B (CALGB) 9782

BACKGROUND

The treatment for prostate cancer patients with biochemical failure after local therapy remains controversial. Peripheral androgen blockade using a combination of a 5-alpha reductase inhibitor and an antiandrogen may allow control of the prostate-specific antigen (PSA). Because testosterone levels are not suppressed, this approach may be associated with less morbidity than conventional gonadal androgen suppression.

METHODS

All patients had undergone previous definitive local therapy and had evidence of a rising PSA >1ng/mL, with no evidence of recurrent disease. Patients received both finasteride, 5 mg orally per day, and flutamide, 250 mg orally 3× a day. Patients were followed for a PSA response and quality of life assessment.

RESULTS

Ninety-nine of 101 accrued patients were eligible. A ≥80% PSA decline was seen in 96 (96%) patients. The median time to PSA progression was 85 months. With a median follow-up of 10 years, the median survival time had not been reached, and the 5-year overall survival rate was 87%. Toxicity was mild, with 18 patients stopping for toxicity; 15 had diarrhea, 4 had gynecomastia, and 3 had transaminase elevation. Baseline Functional Assessment of Cancer Therapy Prostate Module and Treatment Outcome Index scores decreased by 5 points each at 6 months after enrollment.

CONCLUSIONS

The use of the finasteride/flutamide combination is feasible, and results in PSA declines of ≥80% in 96% of patients with serologic progression after definitive local therapy. There were no unexpected toxicities, and the change in quality of life was mild. Further evaluation of this or a similar regimen in a controlled clinical trial is warranted.

Phase II study of cisplatin (C), gemcitabine (G) and gefitinib for advanced urothelial carcinoma (UC): Analysis of the second cohort of CALGB 90102

4578

Background: The epidermal growth factor receptor (EGFR) is frequently expressed in UC and carries a poor prognosis. C has preclinical synergy with gefitinib and GC plus gefitinib was safe in lung cancer patients (pts). In a UC trial of GC using fixed dose rate infusion of G plus gefitinib, Gr 4 and 5 toxicities led to premature closure of the study after 27 patients. Because toxicity was felt to be related to the fixed dose rate infusion of G, accrual was resumed with a standard G dosing schedule in a second cohort. Methods: Eligible pts had measurable N2, N3 or M1 disease; PS of 0–2; CrCl of > 50 ml/min; adequate organ function; no prior systemic combination chemotherapy. Treatment consisted of C 70 mg/m2 D1, G 1000 mg/m2 D1+8 given over 30 min every 3 weeks concurrent with gefitinib 500 mg/day PO for a maximum of 6 cycles. Responders received maintenance gefitinib 500 mg/day until progression. Results: In 55 eligible pts with a median age of 64 years, 67% (of 49) had visceral metastases and 91% had PS of 0–1. Objective response (CR+PR) was observed in 51% (95% CI = 37–65). With a median follow up of 13.2 mo, the median time to progression was 8 mo (95% CI = 6.8–9.2) on the basis of 45 events, and the median overall survival was 14.4 mo (95% CI = 10.7–20.9) on the basis of 26 deaths. No lethal toxicity was seen. Gr 4 toxicities included Gr 4 neutropenia (20%) and Gr 4 metabolic/electrolyte disorders in 13%. Gr 3 and 4 diarrhea was observed in 25% and 2 % of pts respectively and Gr 3 skin rash in 16% of pts. Conclusions: The combination of GC and gefitinib has acceptable toxicity in advanced UC. However, the relative contribution of gefitinib to the efficacy of this regimen remains uncertain. These preliminary results do not suggest a substantial improvement upon historical results with GC alone in advanced UC.

No significant financial relationships to disclose.

Long term efficacy of peripheral androgen blockade on prostate cancer: CALGB 9782

4573

Background: The treatment of patients with a rising PSA after definitive local therapy is controversial. Patients are reluctant to undergo androgen suppression due to side effects and interest focuses on the timing and intensity of additional therapy. The use of peripheral androgen blockade in this setting is appealing. Methods: Patients with a rising PSA after definitive local therapy were enrolled in a multi-institutional trial. Accrual of 101 patients lasted from Sept 30, 1998 to July 16, 2001. All patients had undergone previous definitive local therapy at least 1 year, and no more than 10 years prior to enrollment. All patients had a repeated rising PSA, above 1 ng/ml, with no detectable evidence of recurrent disease. CT and bone scans were negative. Patients received a combination of oral therapy consisting of Finasteride, at a dose of 5 mg/day, and Flutamide, at a dose of 250 mg TID. Results: The median age was 71, with a median baseline testosterone level of 322 ng/dl. A >80% PSA decline was seen in 91/94, (97%) of the patients. Three other patients had PSA declines of 77%, 73% and 38%, all of which were maintained for at least 28 days. The median time to PSA nadir was 3.2 months. The current median follow-up is 59 months. To date, only 22 patients have progressed, with 47 patients still on peripheral androgen blockade. Eight patients have died without progression, and 22 patients went off therapy for other reasons not related to progression. Also noted were patients showing PSA responses to Flutamide withdrawal, and per protocol remaining on Finasteride. Toxicity to date remains very mild. Conclusions: Peripheral androgen blockade showed excellent activity produced durable PSA responses in this select group of patients. While the clinical significance of a decline in PSA alone is not fully understood_the durability of these PSA responses is encouraging. The median duration of progression free survival and overall survival has not been reached, and is likely to be longer than five years. Quality of life data is undergoing further analysis. This report supports further study of less aggressive treatments for patients who have only a rising PSA after definitive local therapy.

No significant financial relationships to disclose.

DNA replication regulation protein Mcm7 as a marker of proliferation in prostate cancer

BACKGROUND

Recent studies have shown that minichromosome maintenance (MCM) proteins (Mcm2-7) may be useful proliferation markers in dysplasia and cancer in various tissues.

AIMS

To investigate the use of Mcm7 as a proliferation marker in 79 lymph node negative prostate cancers and compare it with Ki-67, a commonly used cell proliferation marker.

METHODS

The percentage of proliferating cells (proliferation index; PI) was calculated for basal and luminal epithelial cells in benign prostate tissue, prostatic intraepithelial neoplasia (PIN), and epithelial cells in adenocarcinoma. The PI for each biomarker was correlated with the preoperative prostate specific antigen concentration, the Gleason score, surgical resection margin status, and the AJCC pT stage for each patient.

RESULTS

The mean PIs for Ki-67 and Mcm7 were: benign luminal epithelium 0.7 and 1.2 and benign basal epithelium 0.8 and 8.2; PIN non-basal epithelium 4.9 and 10.6 and PIN basal epithelium 0.7 and 3.1; adenocarcinoma 9.8 and 22.7, respectively. Mcm7 had a significantly higher mean PI (p<0.0001) than Ki-67 for all cell categories except benign luminal epithelial cells. Mcm7 was a better discriminatory marker of proliferation between benign epithelium, PIN, and invasive adenocarcinoma (p<0.0001) than Ki-67. The drop in Mcm7 mean basal cell PI from benign epithelium to PIN epithelium was significantly larger than for Ki-67 (p<0.0001). Mcm7 had a significantly higher PI than Ki-67 at each risk level.

CONCLUSION

Mcm7 may be a useful proliferation marker in prostatic neoplasia and warrants further evaluation as a complementary tool in the diagnosis of PIN and prostate carcinoma.

A comparison of the lactate Pro, Accusport, Analox GM7 and Kodak Ektachem lactate analysers in normal, hot and humid conditions

This study aimed to compare the performance of a new portable lactate analyser against other standard laboratory methods in three conditions, normal (20 +/- 1.3 degrees C; 40 +/- 5 % RH), hot (40 +/- 2.5 degrees C; 40 +/- 5 % RH), and humid (20 +/- 1.1 degrees C; 82 +/- 6 % RH) conditions. Seven healthy males, ([Mean +/- SE]: age, 26.3 +/- 1.3 yr; height, 177.7 +/- 1.6 cm; weight, 77.4 +/- 0.9 kg, .VO(2)max, 56.1 +/- 1.9 ml x kg x min(-1)) undertook a maximal cycle ergometry test to exhaustion in the three conditions. Blood was taken every 3 min at the end of each stage and was analysed using the Lactate Pro LT-1710, the Accusport, the Analox GM7 and the Kodak Ektachem systems. The MANOVA (Analyser Type x Condition x Workload) indicated no interaction effect (F(42,660), = 0.45, p > 0.99, Power = 0.53). The data across all workloads indicated that the machines measured significantly differently to each other (F(4,743) = 14.652, p < 0.0001, Power = 1.00). The data were moderately to highly correlated. We conclude that the Lactate Pro is a simple and effective measurement device for taking blood lactate in a field or laboratory setting. However, we would caution against using this machine to compare data from other machines.

Erythrocyte glutathione deficiency in symptom-free HIV infection is associated with decreased synthesis rate

Although several studies have documented intra- and extracellular glutathione (GSH) deficiency in asymptomatic human immunodeficiency virus (HIV) infection, the mechanisms responsible for the altered GSH homeostasis remain unknown. To determine whether decreased synthesis contributes to this alteration of GSH homeostasis, a primed-constant infusion of [2H2]glycine was used to measure the fractional and absolute rates of synthesis of GSH in five healthy and five symptom-free HIV-infected subjects before and after supplementation for 1 wk with N-acetylcysteine. The erythrocyte GSH concentration of the HIV-infected group was lower (P < 0.01) than that of the control group (1.4 +/- 0.16 vs. 2.4 +/- 0.08 mmol/l). The smaller erythrocyte GSH pool of the HIV-infected group was associated with a significantly slower (P < 0.01) absolute synthesis rate of GSH (1.15 +/- 0.14 vs. 1.71 +/- 0.15 mmol. l-1. day-1) compared with controls. Cysteine supplementation elicited significant increases in both the absolute rate of synthesis and the concentration of erythrocyte GSH. These results suggest that the GSH deficiency of HIV infection is due in part to a reduced synthesis rate secondary to a shortage in cysteine availability.

Pre-clinical evaluation of probes to detect t(8;21) AML minimal residual disease by fluorescence in situ hybridization

The 8;21 translocation in acute myeloid leukemia (AML) results in a consistent fusion transcript, AML1/ETO. Long-term clinical remission occurs in some patients despite incomplete eradication of AML1/ETO as demonstrated by RT-PCR, thus limiting the usefulness of this assay. An important future goal will be to determine if there is a level of minimal residual disease (MRD) in patients below which relapse is unlikely. For the detection of MRD, we have developed reagents for fluorescence in situ hybridization (FISH) that identify both derivative 8 and 21 chromosomes with a high analytical sensitivity. In t(8;21) AML cells, two fused signals were detected in addition to the normal 8 and 21 alleles. The sensitivity and specificity of this probe mixture were analyzed in cell lines and patient bone marrows. One and two randomly juxtaposed signals were observed in 2.4 and 0.04% of normal cells, respectively. However, these were easily differentiated from t(8;21) cells by the absence of signals from the normal alleles. Using as criteria the presence of two fused signals plus the normal alleles, we observed no false positives among 5,000 normal cells. The probe correctly identified 20/20 patients with t(8;21) AML and 10/10 non-t(8;21) patients. In cell dilution experiments, the analytical sensitivity of this reagent was equal to that of the X chromosome and Y chromosome alpha-satellite probes. These optimized probes should facilitate the quantitative assessment and study of MRD in t(8;21) AML.

ETO and AML1 phosphoproteins are expressed in CD34+ hematopoietic progenitors: implications for t(8;21) leukemogenesis and monitoring residual disease

To study acute myelogenous leukemia 1 (AML1) transcription factor, ETO protein, and t(8;21) AML chimeric AML1/ ETO protein in normal hematopoiesis and in leukemia, we raised rabbit antisera to a bacterially expressed polypeptide containing amino acid residues 1 to 220 of ETO and to synthetic peptides extending from residues 528 to 548 of ETO and 32 to 50 of AML1. The latter was selected to have little chance of cross-reactivity with other members of the PEBP2 alpha family. With affinity-purified reagents, we observed immunofluorescent staining for both AML1 and ETO in the nucleus of HEL, K562, and Kasumi-1 leukemic cell lines, the last from a t(8;21) AML. Biochemical analysis confirmed specificity of the antibodies and the nuclear localization of the antigens, the latter being exclusive for AML1 and primary for ETO. Immunoprecipitations of metabolically labeled 32P-proteins from Kasumi-1 cells show that AML1 and ETO are phosphorylated on serine and threonine. Investigations with normal bone marrow reveal AML1 and ETO are coexpressed in megakaryocytes and that each is expressed in a portion of the approximately 10-microns-diameter cells residing there. Using a CD34+ enriched population mobilized to peripheral blood, we found AML1 and, unexpectedly, ETO present in these cells. Because of this, we conclude that the expression of ETO in hematopoietic cells is not by itself leukemogenic. Also, because ETO would not be exclusively expressed as part of chimeric AML1/ETO in leukemic patients, its presence cannot be used to monitor t(8;21) AML residual disease.

Myofibril size variation along the length of extraocular muscle in rabbit and rat. I: orbital layer

It is generally assumed that a muscle fiber is structurally uniform along its length. That assumption is not consistent with the observed variation of myofibrillar profile size along the length of both singly innervated fibers (SIFs) and multiply innervated fibers (MIFs) in the orbital (outer) layer of extraocular muscle (EOM). Muscle fibers were reconstructed in serial sections along the orbital layer of rabbit and rat EOM. For both the SIFs and MIFs, myofibril profile size was smallest (narrowest) near the endplate. In the SIFs of rat, for example, the myofibril profiles were 28% wider at a distance of 1.5 mm from the endplate than at the endplate itself. Measures of profile size included the mean intercept length and the mean shortest path from test points within the profile to the profile boundary. The possible effect of sarcomere length variation was controlled by normalizing the myofibrillar profile size data to a constant spacing of the myosin filament lattice. This morphometric approach was also used to quantify the further increase of profile size that occurs in the end portions of the orbital MIFs where the myobrillar organization is typically ill-defined.

Intermitochondrial junctions in the extraocular muscle of the rat

Intermitochondrial junctions with a spacing of 17-21 nm were observed in the superior rectus muscle of a rat. Periodic rounded densities are aligned midway between the apposed outer mitochondrial membranes at some of these junctions. Such densities have a diameter of about 8-10 nm and a center-to-center spacing of about 26-30 nm. These junctions occur in cases where one mitochondrial profile is enclosed within another or where two profiles are interlocked so that their combined overall form has a smoothly contoured profile. Intermitochondrial junctions seem not to have been previously described in muscle, but have been reported in other kinds of tissues. In agreement with those previous reports, the presently observed intermitochondrial junctions usually involve mitochondria that display atypical features indicative of tissue abnormality or stress. Such junctions were never observed in normal extraocular muscle.

Distribution of mitochondrial and lipidic alterations in abnormal extraocular muscle of rat

An abnormal superior rectus muscle of rat displayed marked differences in the respective distributions of mitochondrial alterations and excessive lipid accumulations, both of which are thought to be indicators of faulty oxidative metabolism. The mitochondrial alterations were widespread, extending over 46% of muscle length. In contrast, the excess lipids extended over but 11% of the muscle length and were virtually confined to the end-plate region. The end plates themselves were essentially normal. These data raise the possibility that the end-plate region may exhibit a locally greater deficit of oxidative metabolism, due to a possibly higher metabolic requirement needed to support the localized end-plate potential activity.

Latter reorganization of membrane-glycogen complexes in rabbit extraocular muscle

Characteristic modes of secondary reorganization were observed in membrane-glycogen complexes of rabbit extraocular muscle. These included (a) an irregular widening or narrowing of the intracisternal space, (b) a loss of the typical intracisternal flocculent densities, and (c) the acquisition of intercisternal flocculent densities. In irregularly widened cisternae, the membranes tended to remain closely adjacent to the intervening glycogen layer, thereby forming triads composed of a glycogen layer enclosed within the apposing membranes of adjacent cisternae. In the absence of glycogen particles from contiguous portions of several lamellae, the membranes became compacted to form myeloidlike figures. Degenerating complexes sometimes displayed distention of intercisternal spaces and layers of atypically small particles. The above modifications of membrane-glycogen complexes would be compatible with the notion that these structures are involved in the process of glycogen metabolism, as opposed to the previously suggested notion that these structures are transient vehicles for the accumulation of glycogen masses.

Membrane-glycogen complexes in rabbit extraocular muscle

Analysis of 432 electron micrographs of membrane-glycogen complexes revealed that: (1) Golgi apparatus is closely associated with 4.2% of the complexes, such associations occurring irrespective of the degree of glycogen loading in the complex. (2) Apparent ribosomes are seen in association with about 30% of the complexes, either attached to membranes or enclosed between cisternae. (3) In longitudinal sections of the muscle fibers, complexes may form columns which extend for as much as 40 microns along the fiber. (4) Various cytoplasmic organelles may become enclosed within a complex. (5) Some cisternae of a complex may assume the form of randomly oriented tubules, in contrast to the typical systematic array of flattened cisternae. (6) Some cisternae of a complex may become distended in a wide and uneven manner, in contrast to the typical narrow and even distension.

Cytoplasmic inclusions in rabbit extraocular muscle

Cytoplasmic inclusion bodies, similar to those previously described in abnormal and normal human extraocular muscle, were observed in the orbital surface layer of the superior rectus muscle in rabbit. These inclusion bodies are composed of a flocculent material of low density studded with granular foci of increased density. In sequential samples of serially reconstructed muscle fibers visualized by electron microscopy, cytoplasmic inclusion bodies were seen in 4.5% of 1187 samples through multiply innervated fibers that vary systematically in diameter along their length; inclusion bodies were also seen in 0.8% of 354 samples through multiple innervated fibers of constant diameter. Cytoplasmic inclusion bodies were not seen in 1838 samples through singly innervated fibers. These data suggest that such inclusion bodies may occur preferentially in multiply innervated fibers. The present findings are not compatible with previous suggestions that such cytoplasmic inclusion bodies may be indicative of a pathologic or aging process. These findings are consistent with previous suggestions that such inclusion bodies are to be considered as normal structures in extraocular muscle.

Variation of mitochondrial volume fraction along multiply innervated fibers in rabbit extraocular muscle

Mitochondrial volume fraction was compared among three regions along the length of six multiply innervated fibers (MIFs) in the orbital surface layer of rabbit superior rectus. These MIFs are of about 5 micrometer diameter toward the middle of their length, and of about 15 micrometer diameter toward their proximal and distal ends. The region of highest volume fraction (26%) was located toward the proximal end of their segment of minimal diameter, in apparent association with endplate-like nerve junctions. The region of lowest volume fraction (8%) was located at their distal segment of maximal diameter. The region toward the distal end of their segment of minimal diameter displayed an intermediate volume fraction (15%). These mitochondrial volume fractions were further analyzed in terms of the relative contributions of the I-band, the A-band, and the subsarcolemmal mitochondrial clusters. Comparable changes in mitochondrial content occur in both the I-band and A-band; in the fibers' distal segment of maximal diameter, however, the mitochondrial volume fraction in the A-band (5%) is lower than in the I-band (11%). These modifications of mitochondrial content along the fibers' length occur irrespective of the contributions of the subsarcolemmal mitochondrial clusters.

The distribution of membrane-glycogen complexes in the orbital surface layer of rabbit superior rectus

The distribution of membrane--glycogen complexes along the length of individual muscle fibers was compared among three fiber populations in the orbital surface layer of rabbit superior rectus. These three populations were (a) 61 singly innervated fibers (SIFs), (b) 10 multiply innervated fibers of relatively constant 10 micrometer diameter (10 micrometer MIFs), and (c) 22 multiply innervated fibers which are of about 5 micrometer diameter toward the middle of their length and of about 15 micrometer diameter toward their proximal and distal segments (5--15 micrometer MIFs). The orbital surface layer was sampled by electron microscopy at 68 sequential locations. Membrane--glycogen complexes were not seen in any of the 1738 samples of the SIFs. In the MIFs, such complexes were observed in 14% of the 1541 samples. However, both the 10 micrometer MIFs and 5--15 micrometer MIFs displayed a preferential concentration of membrane--glycogen complexes toward their distal fiber portions, and such complexes were seen in about 50% of the MIF samples near the beginning of the muscle's distal third. In the distal portion of 5--15 micrometer MIFs, there was a direct relationship between their increasing fiber diameter and their increasing frequency of occurrence of membrane--glycogen complexes.

Structural alterations of the junctional region in extraocular muscle of dystrophic mice. I. Modifications of sole-plate nuclei

Sole-plate nuclei of the C57Bl/6Jdy2j dystrophic mouse showed apparent selective susceptibility to various forms of structural alteration. Pyknosis and chromatin fragmentation were seen in addition to vacuolar and membranous nuclear inclusions. These were often associated with neuromuscular junctions with markedly reduced or virtually absent junctional folding. Membranous proliferations also occurred nearby sole-plate nuclei of such flattened junctions.