Gladell P. Paner

Aire-Dependent Thymic Development of Tumor-Associated Regulatory T Cells

On the Origin of Tumor Tregs The tumor microenvironment is often seeded with regulatory T cells (Tregs), which inhibit antitumor immunity. Using mice with genetically driven prostate cancer, Malchow et al. (p. 1219; see the Perspective by Joshi and Jacks) found a population of Tregs that were enriched in the prostate of tumor-bearing mice. Surprisingly, these cells were also present in female mice and were found to be specific, not for a tumor-specific antigen, but rather for an antigen normally expressed in the prostate. Prostate antigen–specific Tregs arose in the thymus and their selection was dependent on Aire, a protein that drives the expression of tissue-specific antigens in the thymus. Thus, Tregs that seed tumors likely arise in the thymus, are not necessarily tumor-specific, and are recruited and/or expand in an organ when a tumor arises. Prostate tumors in mice recruit thymus-derived regulatory T cells that are specific for tissue autoantigens. [Also see Perspective by Joshi and Jacks] Despite considerable interest in the modulation of tumor-associated Foxp3+ regulatory T cells (Tregs) for therapeutic benefit, little is known about the developmental origins of these cells and the nature of the antigens that they recognize. We identified an endogenous population of antigen-specific Tregs (termed MJ23 Tregs) found recurrently enriched in the tumors of mice with oncogene-driven prostate cancer. MJ23 Tregs were not reactive to a tumor-specific antigen but instead recognized a prostate-associated antigen that was present in tumor-free mice. MJ23 Tregs underwent autoimmune regulator (Aire)–dependent thymic development in both male and female mice. Thus, Aire-mediated expression of peripheral tissue antigens drives the thymic development of a subset of organ-specific Tregs, which are likely coopted by tumors developing within the associated organ.

Chromophobe renal cell carcinoma: Histomorphologic characteristics and evaluation of conventional pathologic prognostic parameters in 145 cases

The aggregate literature suggests that chromophobe renal cell carcinoma (RCC) is biologically a tumor of low malignant potential with reported 5-year and 10-year survival rates of 78% to 100% and 80% to 90%, respectively. The conventional prognostic parameters that determine the outcome of the tumors that progress remain to be fully characterized. Clinicopathologic features of 145 cases were correlated with outcome. The mean age of the patients was 59 years (range, 27 to 82) and the male to female ratio was 1.1:1. Most tumors were well circumscribed and averaged 8.0 cm (range, 1.0 to 30.0 cm); multifocality and bilaterality were present in 8% and 3% of patients. Sixty (41%) were eosinophilic variant (greater than 80% eosinophilic cells), 18 (12%) were classic type (greater than 80% pale cells), and 67 (46%) were mixed (containing variable admixture of pale and eosinophilic cells). A subset of eosinophilic chromophobe RCC contained or had areas similar to renal oncocytomas. These tumors tended to be more commonly bilateral (11%) and multifocal (22%) and were not associated with necrosis or sarcomatoid change. Sarcomatoid change was present in 12/145 (8%) tumors. By histologic grade, 1%, 19%, 74%, 6% were Fuhrman nuclear grade 1, 2, 3, and 4. Nineteen percent, 21%, 28%, 13%, 4%, 1%, and 3% were pT (2002) stage pT1a, pT1b, pT2, pT3a, pT3b, pT3c, and pT4 tumors. Two percent tumors were pN1 at presentation and 2.8% tumors were M1 at presentation. Follow-up (1 to 182 mo, mean 48 mo, median 37 mo) was available in 123 cases. Disease progression (local recurrence 4, metastasis 15, and/or death 10) was seen in 20 patients. In univariable analysis, tumor size (P=0.025), pT stage (P<0.001), broad alveolar architecture (P=0.012), Fuhrman nuclear grade (P<0.001), microscopic tumor necrosis (P=0.001), vascular invasion (P=0.020), and sarcomatoid change (P≤0.001) were associated with progression. A multivariable Cox regression model revealed sarcomatoid change (P=0.013, estimated relative hazard 4.7), microscopic necrosis (P=0.020, relative hazard=3.5), and pT stage (P=0.025, relative hazard 3.4) as independent predictors of aggressive chromophobe RCC. Although the large majority of chromophobe RCCs have a favorable prognosis, a distinct subset of patients progress. The pT stage of tumor, tumor necrosis, and sarcomatoid change all predict aggressive phenotype of chromophobe RCC. The adverse presence of these features in a nephrectomy specimen with chromophobe RCC warrants active surveillance, and these patients may be candidates for adjuvant therapies as they become available.

Tubulocystic carcinoma of the kidney: Clinicopathologic analysis of 31 cases of a distinctive rare subtype of renal cell carcinoma

A distinctive tumor described under the terms Bellini duct carcinoma and low-grade collecting duct carcinoma has been referred to by us and others as tubulocystic carcinoma. This renal cell carcinoma subtype is not recognized in the World Health Organization 2004 classification. Herein, we present a detailed study of 31 cases to further characterize this rare subtype of renal cell carcinoma. The tumor occurred in adults (mean age, 54 years) with a strong male predominance (7:1). Grossly, the tumors ranged from 0.7 to 17 cm, and exhibited a spongy or “bubble wrap” appearance reflecting the microscopic presence of variably sized cystically dilated tubules lined by a single layer of epithelium. The lining varied with a cuboidal, flat, and hobnail cell appearance, and the neoplastic cells had abundant eosinophilic cytoplasm and enlarged nuclei with prominent nucleoli. The cysts were closely spaced with an intervening variably fibrotic stroma. Immunohistochemistry and ultrastructural examination showed features of proximal convoluted tubules (Pax 2 immunoreactivity and short microvilli with brush border organization) and distal nephron (kidney-specific cadherin immunoreactivity and cytoplasmic interdigitation). Gene expression profiling showed that tubulocystic carcinoma displayed a unique molecular signature. Twenty-four tumors were stage pT1, 4 stage pT2, and 3 stage pT3. Disease progression (median follow-up of 56 months) occurred in 3 patients; 1 with local recurrence, and 2 with distant metastasis to bone and liver. In light of the distinctive clinicopathologic features and a low but definite metastatic potential, this unique subtype of renal cell carcinoma deserves formal recognition in the contemporary classification of renal neoplasms.

Immunohistochemical analysis of mucinous tubular and spindle cell carcinoma and papillary renal cell carcinoma of the kidney : Significant immunophenotypic overlap warrants diagnostic caution

Mucinous tubular and spindle cell carcinoma, a rare, recently described distinctive subtype of renal cell carcinoma, may have some morphologic similarities to the more common papillary renal cell carcinoma, particularly the basophilic (type 1) tumors with prominent solid growth pattern. Tumor circumscription, compact tubular architecture, focal papillations, mucin production and foam cells (features seen in both papillary renal cell carcinoma and mucinous tubular and spindle cell carcinoma), as well as spindle cell morphology, have resulted in some cases sent to us in consultation with a question of possible sarcomatoid papillary renal cell carcinoma. In this study, tissue microarrays with triplicate samples each from 27 mucinous tubular and spindle cell carcinomas and 20 papillary renal cell carcinomas were created to simulate experience in renal biopsy specimens. From immunohistochemistry (IHC) data, published in the contemporary literature, a panel consisting of α-methylacyl-CoA racemase (AMACR), cytokeratin 7 (CK7), epithelial membrane antigen (EMA), renal cell carcinoma marker (RCC Ma), CD10, high molecular weight cytokeratin (HMWK), and c-kit was designed to test its utility in differential diagnosis. The immunoreactivity in mucinous tubular and spindle cell carcinoma was AMACR 93%, CK7 81%, EMA 95%, RCC Ma 7%, CD10 15%, HMWK 15%, and c-kit 5% and in papillary renal cell carcinoma was AMACR 95%, CK7 65%, EMA 88%, RCC Ma 25%, CD10 80%, HWMK 15%, and c-kit 18%. This largest study to date on IHC of mucinous tubular and spindle cell carcinoma dispels the specificity of AMACR for papillary renal cell carcinoma among the RCC subtypes. The histogenesis of mucinous tubular and spindle cell carcinoma from the distal nephron continues to be debatable, as our study showed the expression of the proximal convoluted tubule-related marker AMACR among these tumors. Thus, in tumors with predominant compact tubular growth and focal papillary architectures, careful attention to the presence of a low-grade spindle cell population may be helpful in the distinction of mucinous tubular and spindle cell carcinoma, as the key immunohistochemical stains for papillary renal cell carcinoma are also expressed in this subtype of renal cell carcinoma.

Primary thyroid-like follicular carcinoma of the kidney: Report of 6 cases of a histologically distinctive adult renal epithelial neoplasm

Thyroidization of kidney reminiscent of thyroid follicles with accumulation of inspissated colloid-like material in renal tubules is a hallmark of chronic pyelonephritis. We identified 6 tumors in the kidney, distinct from currently known subtypes of renal cell carcinoma, with a striking histology that closely mimicked well-differentiated thyroid follicular neoplasms and raised the possibility of metastatic follicular thyroid carcinoma. Three occurred in males and 3 in females with an age range of 29 to 83 years and size range from 1.9 to 4 cm. All tumors were encapsulated and exclusively demonstrated follicular architecture comprising of microfollicles and macrofollicles containing inspissated colloid-like material. A minor component of small tightly packed follicles devoid of secretions was also noted. The follicles were lined by cells with moderate amphophilic to eosinophilic cytoplasm with round nuclei and occasional prominent nucleoli. The tumors were nonimmunoreactive with thyroglobulin and thyroid transcription factor 1 and for markers contemporarily used for renal differentiation. The tumors had a gene expression profile distinct from clear cell and chromophobe renal cell carcinoma. Comparative genetic hybridization failed to reveal cytogenetic alterations. Mean follow-up of 47.3 months (range: 7 to 84 mo) showed that 5 patients had no evidence of disease and 1 developed a metastasis to the renal hilar lymph nodes in which the follicular architecture with colloid was retained. Thyroid-like follicular renal cell carcinoma represents a unique histologic subtype of renal cell carcinoma of low malignant potential and its primary importance is to distinguish it from metastatic carcinoma from the thyroid.

Neoplasms of the upper urinary tract: a review with focus on urothelial carcinoma of the pelvicalyceal system and aspects related to its diagnosis and reporting.

Tumors of the renal pelvis account for approximately 7% to 8% of all renal malignancies, greater than 90% of these are of urothelial (transitional cell) origin. These tumors more typically occur in the sixth to eight decade with a slight male preponderance. Varying risk factors for urothelial carcinomas of the upper tract are recognized including environmental and occupational hazards, chemotherapeutic exposure, and previous history of urinary bladder or ureteral carcinomas. Tumor multifocality is frequent and additional tumors may arise in the ureter, bladder, or on the contralateral side. The histopathologic nuances presented by urothelial carcinoma in this region are generally similar to those in the urinary bladder. Though the World Health Organization 2004/International Society of Urological Pathology system used in the bladder is customarily also employed for grading of urothelial tumors of this region, its prognostic significance at this site is not entirely clear as most tumors are treated with nephroureterectomy irrespective of the grade of the tumor. Histologic grade may be an independent prognostic factor in papillary pT1 tumors; however, most pT2 and higher stage tumors tend to be nonpapillary and of higher grade. Despite advances in treatment modalities with sophisticated endoscopic techniques, tumor stage remains the most important prognostic factor. There are several confounding issues related to staging such as the variable presence and thickness of subepithelial connective tissue and muscularis in the renal calyces, renal pelvis, and the ureter; intratubular pagetoid cancer spread (pTis vs. pT3); and assessing invasion in papillary neoplasms with endophytic or inverted growth. Careful gross examination with adequate sampling and understanding the microanatomy of the pelvicalyceal wall are crucial for accurate stage assignment. Poor fixation of large friable tumors and processing artifacts may compound difficulties in accurate staging. This review focuses on urothelial carcinoma of the upper tract highlighting issues related to its diagnosis, staging, and reporting.

A Novel Tumor Grading Scheme for Chromophobe Renal Cell Carcinoma: Prognostic Utility and Comparison With Fuhrman Nuclear Grade

Chromophobe renal cell carcinoma (RCC) is a histologic subtype of RCC that portends a favorable prognosis. It is controversial whether the Fuhrman nuclear grade of chromophobe RCC has prognostic utility. Irregular nuclei, prominent nucleoli, and nuclear pleomorphism are inherently present in chromophobe RCC. Hence, the Fuhrman nuclear grade is higher even though the majority of these tumors have a favorable outcome. In this study, the prognostic utility of a novel 3-tiered tumor grading system in which the innate nuclear atypia of chromophobe RCC was discounted, herein referred to as chromophobe tumor grade from a series of 124 chromophobe RCC, was compared with Fuhrman nuclear grade. Chromophobe tumor grade is based on the assessment of geographic nuclear crowding and anaplasia. The Fuhrman nuclear grade distribution between the tumors was grade 1 (1%), grade 2 (19%), grade 3 (74%), and grade 4 (6%), whereas the chromophobe tumor grade distribution was grade 1 (74%), grade 2 (16%), and grade 3 (10%). Neither Fuhrman nuclear grade nor chromophobe tumor grade was significantly associated with patients age or sex and chromophobe RCC cell types, but both showed a significant association with tumor size. Both Fuhrman nuclear grade and chromophobe tumor grade showed statistically significant positive associations with broad alveolar growth, necrosis, vascular invasion, and with pathologic stage; however, all these associations tended to be dictated by tumors with sarcomatoid change. When tumors with sarcomatoid change were excluded, a strong positive association persisted between chromophobe tumor grade and pathologic stage. In contrast, there was no such association between Fuhrman nuclear grade and stage in nonsarcomatoid chromophobe RCCs. Characterizing aggressive chromophobe RCC with aggressive behavior with the time from surgery to first occurrence of metastasis, local recurrence, or death owing to disease, we found that both Fuhrman nuclear grade and chromophobe tumor grade were highly associated with adverse outcome. However, as with the pathologic stage, only a significant association between chromophobe tumor grade and outcome was retained among nonsarcomatoid chromophobe RCCs. Multivariable Cox regression analysis also tended to support chromophobe tumor grade rather than Fuhrman nuclear grade as an independent predictor of adverse outcome, controlling for other univariably significant risk factors [estimated relative hazard=3.68 (P=0.026) vs. 1.86 (P=0.42)]. In conclusion, the novel chromophobe tumor grading system proposed herewith provides superior prognostic value to that of the Fuhrman nuclear grade in chromophobe RCC and will potentially help stratify patients of chromophobe RCC who are at a greater risk of disease progression.

Mucinous Tubular and Spindle Cell Carcinoma of the Kidney With Sarcomatoid Change

Sarcomatoid change has been well documented in the various subtypes of renal cell carcinoma (RCC) and its presence is known to portend a worse prognosis in RCC. Mucinous tubular and spindle cell carcinoma is a RCC subtype, which is defined as polymorphous histology wherein the spindled epithelial cell is an inherent carcinomatous component. Many of these putatively low-grade tumors have been previously misdiagnosed as unclassified or sarcomatoid papillary RCC. We present 2 examples of hitherto undescribed sarcomatoid change in mucinous tubular and spindle cell carcinoma in a 71-year-old woman and an 80-year-old man who both underwent a radical nephrectomy procedure. In addition to the classic mucinous tubular and spindle cell carcinoma morphology, both cases had a sarcomatoid component characterized by predominantly high-grade spindle cells, solid pleomorphic epithelioid cells, and malignant fibrous histiocytoma-like storiform patterns. Sarcomatoid change comprised 60% and 20% of the tumors, respectively. Unlike the spindle sarcomatoid cells, the inherent spindle cell elements of mucinous tubular and spindle cell carcinoma had distinctively low-grade cytology and occasionally blended with tubular structures and variable mucinous stroma. The sarcomatoid cells were associated with significant necrosis, marked nuclear pleomorphism, mitoses of up to 5/10 high power field, higher proliferation fraction (MIB1), and loss of α-methylacyl-CoA racemase or cytokeratin 7 expression. Cytogenetic analysis in 1 tumor showed loss of chromosomes 14 and 15 and gains of chromosomes 2, 5, 7, 9, 10, 12, 17, 19, 20, 22, and X. Widespread metastasis to lymph nodes, bones and lungs occurred in one patient who succumbed 9 months after nephrectomy. Helpful features in distinguishing spindle cells of sarcomatoid component versus that of the native tumor include the presence of high-grade cytology, expansile growth with loss of typical imperceptible blending with the tubulo-papillary component, extensive necrosis, high mitotic activity, high proliferation fraction, and loss of expression of α-methylacyl-CoA racemase that contrasted the classic areas. Distinction of the sarcomatoid histology from inherent spindle cell component of mucinous tubular and spindle cell carcinoma is important because of its unfavorable prognostic implication.

Molecular Drivers of the Non-T-cell-Inflamed Tumor Microenvironment in Urothelial Bladder Cancer.

Immunotherapy resistance is a reality for many cancer patients. Three tumor-intrinsic molecular pathways, β-catenin, PPARγ, and FGFR3, were identified and linked to the exclusion of T cells from urothelial tumors. Targeting these pathways may enhance immune checkpoint efficacy. Muscle-invasive urothelial bladder cancer is a common malignancy with poor outcomes for which immune checkpoint blockade is now showing promise. Despite clinical activity of PD-1/PD-L1–targeted therapy in this disease, most patients do not benefit and resistance mechanisms remain unknown. The non–T-cell-inflamed tumor microenvironment correlates with poor prognosis and resistance to immunotherapies. In this study, we determined tumor-oncogenic pathways correlating with T-cell exclusion. We first establish in this report that T-cell–inflamed bladder tumors can be identified by immune gene expression profiling with concordance with CD8+ T-cell infiltration. Upregulation of genes encoding immune checkpoint proteins PD-L1, IDO, FOXP3, TIM3, and LAG3 was associated with T-cell–inflamed tumors, suggesting potential for sensitivity to checkpoint blockade. β-Catenin, PPAR-γ, and FGFR3 pathways were activated in non–T-cell-inflamed tumors. No difference was seen in overall somatic mutational density between groups. The three pathways identified represent targetable potential pathways of tumor-intrinsic immunotherapy resistance. Cancer Immunol Res; 4(7); 563–8. ©2016 AACR.

Sox2 Is an Androgen Receptor-Repressed Gene That Promotes Castration-Resistant Prostate Cancer

Despite advances in detection and therapy, castration-resistant prostate cancer continues to be a major clinical problem. The aberrant activity of stem cell pathways, and their regulation by the Androgen Receptor (AR), has the potential to provide insight into novel mechanisms and pathways to prevent and treat advanced, castrate-resistant prostate cancers. To this end, we investigated the role of the embryonic stem cell regulator Sox2 [SRY (sex determining region Y)-box 2] in normal and malignant prostate epithelial cells. In the normal prostate, Sox2 is expressed in a portion of basal epithelial cells. Prostate tumors were either Sox2-positive or Sox2-negative, with the percentage of Sox2-positive tumors increasing with Gleason Score and metastases. In the castration-resistant prostate cancer cell line CWR-R1, endogenous expression of Sox2 was repressed by AR signaling, and AR chromatin-IP shows that AR binds the enhancer element within the Sox2 promoter. Likewise, in normal prostate epithelial cells and human embryonic stem cells, increased AR signaling also decreases Sox2 expression. Resistance to the anti-androgen MDV3100 results in a marked increase in Sox2 expression within three prostate cancer cell lines, and in the castration-sensitive LAPC-4 prostate cancer cell line ectopic expression of Sox2 was sufficient to promote castration-resistant tumor formation. Loss of Sox2 expression in the castration-resistant CWR-R1 prostate cancer cell line inhibited cell growth. Up-regulation of Sox2 was not associated with increased CD133 expression but was associated with increased FGF5 (Fibroblast Growth Factor 5) expression. These data propose a model of elevated Sox2 expression due to loss of AR-mediated repression during castration, and consequent castration-resistance via mechanisms not involving induction of canonical embryonic stem cell pathways.