Scott B. Shappell

Prostate Pathology of Genetically Engineered Mice: Definitions and Classification. The Consensus Report from the Bar Harbor Meeting of the Mouse Models of Human Cancer Consortium Prostate Pathology Committee

The Pathological Classification of Prostate Lesions in Genetically Engineered Mice (GEM) is the result of a directive from the National Cancer Institute Mouse Models of Human Cancer Consortium Prostate Steering Committee to provide a hierarchical taxonomy of disorders of the mouse prostate to facilitate classification of existing and newly created mouse models and the translation to human prostate pathology. The proposed Bar Harbor Classification system is the culmination of three meetings and workshops attended by various members of the Prostate Pathology Committee of the Mouse Models of Human Cancer Consortium. A 2-day Pathology Workshop was held at The Jackson Laboratory in Bar Harbor, Maine, in October 2001, in which study sets of 93 slides from 22 GEM models were provided to individual panel members. The comparison of mouse and human prostate anatomy and disease demonstrates significant differences and considerable similarities that bear on the interpretation of the origin and natural history of their diseases. The recommended classification of mouse prostate pathology is hierarchical, and includes developmental, inflammatory, benign proliferative, and neoplastic disorders. Among the neoplastic disorders, preinvasive, microinvasive, and poorly differentiated neoplasms received the most attention. Specific criteria were recommended and will be discussed. Transitions between neoplastic states were of particular concern. Preinvasive neoplasias of the mouse prostate were recognized as focal, atypical, and progressive lesions. These lesions were designated as mouse prostatic intraepithelial neoplasia (mPIN). Some atypical lesions were identified in mouse models without evidence of progression to malignancy. The panel recommended that mPIN lesions not be given histological grades, but that mPIN be further classified as to the absence or presence of documented associated progression to invasive carcinoma. Criteria for recognizing microinvasion, for classification of invasive gland-forming adenocarcinomas, and for characterizing poorly differentiated tumors, including neuroendocrine carcinomas, were developed and are discussed. The uniform application of defined terminology is essential for correlating results between different laboratories and models. It is recommended that investigators use the Bar Harbor Classification system when characterizing new GEM models or when conducting experimental interventions that may alter the phenotype or natural history of lesion progression in existing models.

Clinical under staging of high risk nonmuscle invasive urothelial carcinoma treated with radical cystectomy.

PURPOSE The role of radical cystectomy in patients with nonmuscle invasive urothelial carcinoma of the bladder remains controversial. The risk of overtreatment must be balanced against the potential benefit of aggressive therapy. We reviewed our results in these patients with a particular emphasis on clinical under staging. MATERIALS AND METHODS We reviewed the records of 214 consecutive patients who underwent radical cystectomy for urothelial carcinoma between April 1995 and August 1999, focusing on those with nonmuscle invasive, stages T1 or less disease. We assessed clinical and pathological data as well as outcomes based on pathological disease extent. RESULTS A total of 78 patients (36%) underwent radical cystectomy for clinical stages T1 or less disease. Indications included disease refractory to intravesical therapy in 29 cases (37%), pathological findings reflective of high grade stage T1 or multifocal disease in 26 (33%), radiographic suspicion of invasive disease in 15 (20%) and severe symptoms in 8 (10%). Cancer was clinically under staged with stages pT2 or greater disease in 31 patients (40%) according to final pathology results. Under staging was most pronounced in the 10 patients (67%) with suspicious radiography and in the 18 (64%) with absent muscle in the biopsy specimen. Of the 78 patients with pathological stages pT1 disease or less 98% had no evidence of disease compared to 65% with stages pT2 or greater disease (p <0.01). CONCLUSIONS Despite the intent to perform early cystectomy a significant percent of patients harbored occult muscle invasive and/or metastatic disease. In clinical and pathological, superficial stages T1 or less cases disease-free survival was excellent. Due to these results, the selection of high risk superficial transitional cell carcinoma cases for continued bladder sparing treatment should include uninvolved muscle on biopsy and absent radiographic suspicion of invasion.

Incidence and Location of Prostate and Urothelial Carcinoma in Prostates From Cystoprostatectomies: Implications for Possible Apical Sparing Surgery

PURPOSE Prostatic carcinoma (Pca) at cystoprostatectomy is usually an incidental finding with the majority thought to be clinically insignificant. Most studies have not specifically addressed the location of Pca or the incidence and location of in situ or invasive urothelial carcinoma (Uca) in prostates of cystoprostatectomy specimens. The frequency of involvement of the apex with these processes has clinical implications. Specifically urinary continence following orthotopic diversion may be enhanced by prostate apical sparing. In this study the pathological features of Pca and Uca, and the frequency of apical involvement were investigated in prostates from cystoprostatectomy specimens. MATERIALS AND METHODS Whole mounted prostates from 121 consecutive cystoprostatectomy specimens were analyzed. Pca location, tumor volume, grade, stage, surgical margin and pelvic lymph node status of Pcas were assessed. Clinically insignificant Pcas had a volume of less than 0.5 cc without Gleason pattern 4, extracapsular extension, seminal vesicle invasion, lymph node involvement or positive surgical margins. Prostate involvement by Uca or urothelial carcinoma in situ (CIS)/severe dysplasia and its location were assessed. RESULTS Of 121 prostates 50 (41%) had unsuspected Pca, of which 24 (48%) were clinically significant. Of Pcas 30 of 50 (60%) involved the apex, including 19 of 24 (79%) that were significant and 11 of 26 (42%) that were insignificant. Of 121 prostates 58 (48%) had Uca involving the prostatic stroma, noninvasive Uca or urothelial CIS/severe dysplasia in the prostatic urethra or periurethral ducts, of which 19 (33%) had apical involvement. Overall only 32 of 121 patients (26%) had no Pca or prostate Uca/CIS and only 45 (37%) had no clinically significant Pca or Uca/CIS in the prostate. However, 74 of the 121 patients (61%) had no prostatic apical involvement by Pca or Uca/CIS and 85 (70%) had no apical involvement by clinically significant Pca or Uca/CIS. Patients with prostatic apical involvement by invasive or in situ Uca uniformly had involvement of more proximal (toward the base) portions of the prostate. CONCLUSIONS The majority of prostates from cystoprostatectomies had no involvement of the prostatic apex by Uca or clinically significant Pca. Hence, most patients may be candidates for prostate apical sparing. However, involvement of the apex by Uca in any patient raises concern about procedures that leave portions of the prostate urethra after cystectomy in an effort to improve continence. In candidates for orthotopic neobladder reconstruction removing all of the prostatic urethra and sparing the remainder of the prostatic apex may allow improved preservation of urinary continence with an acceptable low risk of clinical Pca progression. Whether future strategies for preoperative exclusion of apical Pca and intraoperative assessment of more proximal prostate to help exclude apical urothelial disease may identify patients suitable for prostatic apical sparing remains to be determined. The impact on functional outcomes and cancer control also require additional study.

15-Lipoxygenase-2 (15-LOX-2) Is Expressed in Benign Prostatic Epithelium and Reduced in Prostate Adenocarcinoma

Human 15S-lipoxygenase-2 (15-LOX-2) is a recently identified lipoxygenase that has approximately 40% sequence identity to the known human 5S-, 12S-, and 15S-lipoxygenases. 15-LOX-2 has a limited tissue distribution, with mRNA detected in prostate, lung, skin, and cornea, but not in numerous other tissues, including peripheral blood leukocytes. In the current study, we have characterized the distribution of 15-LOX-2 in the human prostate by immunohistochemistry, demonstrated the ability of benign prostate tissue to form 15S-hydroxyeicosatetraenoic acid (15S-HETE) from exogenous arachidonic acid (AA), and begun characterizing possible alterations in 15-LOX-2 in prostate adenocarcinoma. Incubation of benign prostate tissue with [14C]AA resulted in formation of [14C]15-HETE, as determined by reverse- and straight-phase high-performance liquid chromatography. 15-HETE was the major AA metabolite formed. By immunohistochemistry, 15-LOX-2 is located in secretory cells of peripheral zone glands and large prostatic ducts and somewhat less uniformly in apical cells of transition and central zone glands. 15-LOX-2 was not detected in the basal cell layer, stroma, ejaculatory ducts, seminal vesicles, or transitional epithelium. Immunostaining of 18 radical prostatectomy specimens showed a loss of 15-LOX-2 in the majority of prostate adenocarcinomas; 14 of 18 cases showed loss of 15-LOX-2 in >25% of the tumor (mean, 74.9% negative for 15-LOX-2; range, 38.9% to 100%). Incubation of paired pure benign and pure malignant prostate tissue from the same radical prostatectomies showed that 15-HETE formation was markedly reduced (>90%) or undetectable in incubations of prostate adenocarcinoma. 15-LOX-2 is a novel human lipoxygenase with a limited tissue distribution that is strongly expressed in benign prostate glandular epithelium and lost to a variable degree in the majority of prostate adenocarcinomas.

Enhanced Expression of Cyclooxygenase-2 in High Grade Human Transitional Cell Bladder Carcinomas

Studies in human and animal models have shown that cyclooxygenase (COX)-2 is up-regulated in several epithelial carcinomas including colon, breast, and lung. To elucidate the possible involvement of COX-2 in human bladder cancer we examined the expression of COX isoforms in benign tissue and in bladder carcinoma specimens. Paraffin embedded tissues from 75 patients with urothelial carcinomas were immunostained with specific antibodies raised against COX-1 and COX-2. COX-1 expression was detected in smooth muscle cells in both benign and malignant bladders. COX-2 immunoreactivity was absent in benign tissue and in specimens with low-grade urothelial carcinoma (0/23). In contrast, expression of COX-2 was detected in malignant epithelial cells in 38% (17/47) of specimens with high-grade urothelial carcinomas. Expression of COX-2 in high-grade bladder cancer was confirmed by radioactive in situ hybridization using a COX-2-selective riboprobe. Both immunohistochemistry and in situ hybridization showed COX-2 expression in a small subset of malignant cells. COX-2 mRNA was also expressed in three out of seven malignant urothelial cell lines. These data demonstrate elevated expression of COX-2 in a high percentage of high-grade bladder carcinomas, suggesting a possible role of COX-2 in the progression of bladder urothelial carcinoma and supporting its potential as a therapeutic target in human bladder carcinoma.

Forkhead box A1 regulates prostate ductal morphogenesis and promotes epithelial cell maturation

We have previously shown that a forkhead transcription factor Foxa1 interacts with androgen signaling and controls prostate differentiated response. Here, we show the mouse Foxa1 expression marks the entire embryonic urogenital sinus epithelium (UGE), contrasting with Shh and Foxa2, which are restricted to the basally located cells during prostate budding. The Foxa1-deficient mouse prostate shows a severely altered ductal pattern that resembles primitive epithelial cords surrounded by thick stromal layers. Characterization of these mutant cells indicates a population of basal-like cells similar to those found in the embryonic UGE, whereas no differentiated or mature luminal epithelial cells are found in Foxa1-deficient epithelium. These phenotypic changes are accompanied with molecular aberrations, including focal epithelial activation of Shh and elevated Foxa2 and Notch1 in the null epithelium. Perturbed epithelial-stromal interactions induced by Foxa1-deficient epithelium is evident, as demonstrated by the expansion of surrounding smooth muscle and elevated levels of stromal factors (Bmp4, Fgf7, Fgf10 and Gli). The prostatic homeobox protein Nkx3.1, a known proliferation inhibitor, was downregulated in Foxa1-deficient epithelial cells, while several prostate-specific androgen-regulated markers, including a novel Foxa1 target, are absent in the null prostate. These data indicate that Foxa1 plays a pivotal role in controlling prostate morphogenesis and cell differentiation.

NE-10 neuroendocrine cancer promotes the LNCaP xenograft growth in castrated mice.

Increases in neuroendocrine (NE) cells and their secretory products are closely correlated with tumor progression and androgen-independent prostate cancer. However, the mechanisms by which NE cells influence prostate cancer growth and progression, especially after androgen ablation therapy, are poorly understood. To investigate the role of NE cells on prostate cancer growth, LNCaP xenograft tumors were implanted into nude mice. After the LNCaP tumors were established, the NE mouse prostate allograft (NE-10) was implanted on the opposite flank of these nude mice to test whether NE tumor-derived systemic factors can influence LNCaP growth. Mice bearing LNCaP tumors with or without NE allografts were castrated 2 weeks after NE tumor inoculation, and changes in LNCaP tumor growth rate and gene expression were investigated. After castration, LNCaP tumor growth decreased in mice bearing LNCaP tumors alone, and this was accompanied by a loss of nuclear androgen receptor (AR) localization. In contrast, in castrated mice bearing both LNCaP and NE-10 tumors, LNCaP tumors continued to grow, had increased levels of nuclear AR, and secreted prostate-specific antigen. Therefore, in the absence of testicular androgens, NE secretions were sufficient to maintain LNCaP cell growth and androgen-regulated gene expression in vivo. Furthermore, in vitro experiments showed that NE secretions combined with low levels of androgens activated the AR, an effect that was blocked by the antiandrogen bicalutamide. Because an increase in AR level has been reported to be sufficient to account for hormone refractory prostate cancers, the NE cell population ability to increase AR level/activity can be another mechanism that allows prostate cancer to escape androgen ablation therapy.

Tumour volume is an independent predictor of prostate‐specific antigen recurrence in patients undergoing radical prostatectomy for clinically localized prostate cancer

Authors from the USA sought to establish the relationship between tumour volume, pathological stage and outcomes after radical prostatectomy. In a large series of patients they found that tumour volume was correlated directly with pathological stage, and that it was independently correlated with PSA recurrence. The authors suggested that tumour volume had a potential use for prognostication in patients undergoing radical prostatectomy.

Recurrent lupus nephritis in renal transplant recipients revisited: It is not rare

Background. Although recurrent lupus nephritis (RLN) after kidney transplantation is reported to be rare (1%–4%), recent studies suggest a higher incidence. The purpose of this study was to determine the incidence of RLN in a large cohort of renal transplant recipients with systemic lupus erythematosus (SLE). Methods. The records of 54 renal transplant recipients with SLE were reviewed. Thirty-one patients underwent biopsy because of worsening renal function and proteinuria. All biopsy specimens were evaluated by light microscopy, immunofluorescence (IF), and electron microscopy (EM). Results. Among the 50 patients with at least 3 months of follow-up, RLN was present in 15 (52% of patients who underwent biopsy, 30% of total patients): mesangial lupus nephritis (LN) (class II) in eight, focal proliferative LN (class III) in four, and membranous LN (class Vb) in three patients. One patient had graft loss because of RLN (class II) at 10.5 years. The duration of dialysis before transplantation was not different between patients with RLN compared to patients without RLN (P =0.40). Overall patient survival (n=50) was 96% at 1 year and 82% at 5 years, and graft survival was 87% at 1 year and 60% at 5 years. Graft survival was worse in patients who underwent biopsy compared with patients who never underwent biopsy (P <0.01). Conclusions. RLN is more common than previously reported, but in our series, graft loss because of RLN was rare. Aggressive use of allograft biopsies and morphologic evaluation with IF and EM are important factors in the diagnosis of RLN. The impact of new immunosuppressive agents on the incidence of RLN remains to be seen.

Percent Of Cancer in the Biopsy Set Predicts Pathological Findings After Prostatectomy

PURPOSE The ability to use pretreatment variables to identify patients with organ confined prostate cancer continues to challenge physicians. We examined information available preoperatively, including prostate needle biopsy, clinical stage and preoperative prostate specific antigen (PSA), and evaluated these data based on pathological variables after radical retropubic prostatectomy. MATERIALS AND METHODS We reviewed results in 135 consecutive patients who underwent radical retropubic prostatectomy at a single institution. Needle biopsy information, such as the number of cores, percent of tumor per biopsy set, laterality of positive cores and Gleason sum, were compared with pathological data on the radical retropubic prostatectomy specimen, including pathological stage, Gleason sum and tumor volume. Clinical data, including biopsy information and pathological findings, were compared using univariate and multivariate models. RESULTS Overall total PSA, percent of tumor in the biopsy and bilateral positive cores directly correlated with tumor volume (p <0.01). Also, increasing PSA, increasing percent of tumor in the biopsy and bilateral positive cores were associated with increased risks of extracapsular extension (p <0.01). CONCLUSIONS From the information readily available from prostate needle biopsy these results suggest that percent of tumor in the biopsy is a useful predictor of pathological stage and tumor volume. Furthermore, including percent of tumor in the biopsy set and bilateral disease with traditional variables such as serum PSA and clinical stage may improve pretreatment tumor staging. This finding adds additional credence to the inclusion of percent of tumor in the biopsy set in models for the preoperative prediction of pathological stage and should be factored into discussions with patients on treatment options.