Payal Kapur

Interplay Between pVHL and mTORC1 Pathways in Clear-Cell Renal Cell Carcinoma

mTOR complex 1 (mTORC1) is implicated in cell growth control and is extensively regulated. We previously reported that in response to hypoxia, mTORC1 is inhibited by the protein regulated in development and DNA damage response 1 (REDD1). REDD1 is upregulated by hypoxia-inducible factor (HIF)-1, and forced REDD1 expression is sufficient to inhibit mTORC1. REDD1-induced mTORC1 inhibition is dependent on a protein complex formed by the tuberous sclerosis complex (TSC)1 and 2 (TSC2) proteins. In clear-cell renal cell carcinoma (ccRCC), the von Hippel-Lindau (VHL) gene is frequently inactivated leading to constitutive activation of HIF-2 and/or HIF-1, which may be expected to upregulate REDD1 and inhibit mTORC1. However, mTORC1 is frequently activated in ccRCC, and mTORC1 inhibitors are effective against this tumor type; a paradox herein examined. REDD1 was upregulated in VHL-deficient ccRCC by in silico microarray analyses, as well as by quantitative real-time PCR, Western blot, and immunohistochemistry. Vhl disruption in a mouse model was sufficient to induce Redd1. Using ccRCC-derived cell lines, we show that REDD1 upregulation in tumors is VHL dependent and that both HIF-1 and HIF-2 are, in a cell-type-dependent manner, recruited to, and essential for, REDD1 induction. Interestingly, whereas mTORC1 is responsive to REDD1 in some tumors, strategies have evolved in others, such as mutations disrupting TSC1, to subvert mTORC1 inhibition by REDD1. Sequencing analyses of 77 ccRCCs for mutations in TSC1, TSC2, and REDD1, using PTEN as a reference, implicate the TSC1 gene, and possibly REDD1, as tumor suppressors in sporadic ccRCC. Understanding how ccRCCs become refractory to REDD1-induced mTORC1 inhibition should shed light into the development of ccRCC and may aid in patient selection for molecular-targeted therapies. Mol Cancer Res; 9(9); 1255–65. ©2011 AACR.

Characterization of Inflammation in Syphilitic Villitis and in Villitis of Unknown Etiology

Chronic villitis is a histologic diagnosis that may be either associated with infection, or termed villitis of undetermined etiology (VUE). The lymphocytic infiltrate in VUE has been reported to consist of maternal lymphocytes, but the origin of the lymphocytic infiltrate in infectious villitis has not been identified. The purpose of our study was to compare the maternal vs. fetal origin of the infiltrating lymphocytes in VUE and syphilitic villitis, and to expand the immunophenotypic data provided by previous studies. Paraffin-embedded placentas from four males with VUE and two males with syphilitic villitis were subjected to fluorescence in situ hybridization (FISH) for the X and Y chromosomes. Serial sections were stained with antibodies to CD3, CD4, CD8, CD68, HLA-DR, and CD20. Quantitation of the relative number of cells marking with each antibody was done for four villi in each slide. CD3 lymphocytes predominated in both VUE and syphilitic villitis, with slightly more CD8 cells compared to CD4 cells. CD68 and HLA-DR positive cells were as frequent as CD3 cells, and B-lymphocytes were rare. Maternal cells were the predominant intravillous population in both VUE and syphilitic villitis, and neutrophils in syphilitic villitis were also maternal. These data indicate that the immune response in both syphilitic villitis and VUE is similar, raising the possibility of a similar immunopathogenetic pathway.

Tissue microarray constructs to predict a response to chemoradiation in rectal cancer

PURPOSEnTo identify, using tissue microarray (TMA), an immunohistochemical panel predictive of response to ionizing radiation (IR) in rectal cancer.nnnMETHODSnTMA constructs were prepared from archived stage II/III rectal tumors and matching adjacent mucosa (n=38) from patients treated with pre-operative chemoradiation. Immunohistochemistry (IHC) was performed for MIB, Cyclin E, p21, p27, p53, survivin, Bcl-2, and BAX. Immunoreactivity along with clinical variables was subjected to univariate and forward stepwise logistic regression analyses.nnnRESULTSnPathological complete response (pCR) was 23.9%. The number of positive lymph nodes obtained in the resected specimen was associated with pCR. Immunoreactivity for MIB (Sn 15%, Sp 65%, OR 0.33), p53 (Sn 3%, Sp 84%, OR 0.16), Bcl-2 (Sn 11%, Sp 74%, OR 0.35), and BAX (Sn 92%, Sp 80%, OR 46) was associated with pathological response (all ps<0.001). Forward stepwise logistic regression analysis demonstrated that MIB was an independent predictor of a response to chemoradiation (p=0.001).nnnCONCLUSIONSnA combined panel of mediators of apoptosis alone or combined with clinical factors is a feasible approach that can be applied to rectal tumor biopsies to predict a response to chemoradiation. The most sensitive factor was BAX; while MIB independently predicted a response to chemoradiation.

Microsatellite instability among individuals of Hispanic origin with colorectal cancer

Although the presence of microsatellite instability (MSI) in patients with colorectal cancer (CRC) may have implications for prognosis, therapy, and family counseling, to the authors knowledge, the prevalence of MSI has not been well described among individuals of Hispanic origin with CRC residing in the United States.

Expression of cell cycle–related molecular markers in patients treated with radical cystectomy for squamous cell carcinoma of the bladder

We evaluated the association of p53, p21, p27, cyclin E, and Ki-67 expression with pathologic features and clinical outcomes of patients with squamous cell carcinoma (SCC) of the urinary bladder. Immunohistochemical staining was performed on radical cystectomy specimens with pure SCC from 1997 to 2003. Bright field microscopy imaging coupled with advanced color detection software was used. The relationship between these markers and pathologic parameters as well as clinical outcome was assessed. The study included 152 patients (80.9% with bilharziasis), 99 males and 53 females, with a median age of 51 years (range, 36-74 years). The presenting stage was T2 or higher, and the presenting grade was grade II or lower in 93.4% of patients. Altered cyclin E expression was associated with stages (P = .02), altered p21 with grades (P = .02), and altered p27 with lymphovascular invasion (P = .01). In multivariable analyses, altered p53 expression was the only marker associated with an increased risk of disease recurrence (hazards ratio, 1.77; 95% confidence interval, 1.03-3.38, P = .04; and hazards ratio, 2.28; 95% confidence interval, 1.01-5.70, P = .05) and bladder cancer-specific mortality (hazards ratio, 1.76; 95% confidence interval, 1.06-2.99, P = .05, and hazards ratio, 2.64; 95% confidence interval, 1.05-5.54, P = .05) in all patients and in patients with T1-3N0 tumors, respectively. In conclusion, cell cycle-related molecular markers are commonly altered in SCC of the urinary bladder. Only p53 had a prognostic role in patients treated with radical cystectomy for SCC. Our findings support the need for further evaluation of molecular markers and their signaling pathways in SCC.

Primary adenocarcinoma of the urinary bladder: value of cell cycle biomarkers.

Primary adenocarcinomas of the urinary bladder are uncommon, and the molecular pathways are currently not well defined. In this study, we assessed the association between biologic markers and clinicopathologic characteristics in a cohort of 21 patients with primary urinary bladder adenocarcinoma. Immunohistochemical staining for cell cycle-specific markers, including p53, p21, p27, Ki-67, and cyclin E, were performed on sections of a tissue microarray construct. The tumors were high grade in 12 (57%) and pT2 or higher in 18 (86%); lymph nodes were involved in 6 cases (29%); and there was pathologic evidence of schistosomiasis in 14 (67%). The best prognostic combination of markers was combined alterations in p27 and Ki-67 and was associated with stage (P = .012), grade (P = .005), DNA ploidy (P = .005), and lymph node involvement (P = .04). Stage, lymph node involvement, combined alterations of p27 and Ki-67, and combined alterations of all 5 biomarkers were associated with increased probability of disease recurrence and cancer-specific mortality (P < .05).

Bilharzial vs non-bilharzial related bladder cancer: pathological characteristics and value of cyclooxygenase-2 expression

Study Type – Prognostic (case series) u2028Level of Evidenceu20034

Prognostic Value of Cyclooxygenase-2 Expression in Squamous Cell Carcinoma of the Bladder

PURPOSEnInflammation is associated with the pathogenesis of carcinoma, including squamous cell carcinoma of the bladder. Cyclooxygenase-2 is an enzyme that is induced at inflammation sites. We assessed the expression pattern of cyclooxygenase-2 in patients with squamous cell carcinoma of the bladder and determined whether cyclooxygenase-2 expression is associated with clinical outcomes after radical cystectomy.nnnMATERIALS AND METHODSnImmunohistochemical staining for cyclooxygenase-2 was done on archival bladder specimens from 152 patients treated with radical cystectomy for squamous cell carcinoma on the Autostainer (DakoCytomation, Carpinteria, California). Bright field microscopy imaging coupled with advanced color detection software was used. Cyclooxygenase-2 was defined as over expressed when greater than 20% cells were positive. We assessed the relationship of cyclooxygenase-2 expression with pathological parameters and clinical outcome.nnnRESULTSnThe study included 99 male and 53 female patients with a mean age of 52 years who had squamous cell carcinoma, including 80.9% with bilharziasis. Presenting stage was T2 or greater and presenting grade was GII or less in 93.4% of patients. Median followup was 63.2 months. Cyclooxygenase-2 was over expressed in 74 cystectomy specimens (48.7%) and associated with higher pathological stage (p=0.003) and grade (p=0.049). On multivariate Cox proportional hazards regression analysis cyclooxygenase-2 over expression was associated with disease recurrence (p=0.031) and bladder cancer specific mortality (p=0.046).nnnCONCLUSIONSnCyclooxygenase-2 over expression is associated with pathological stage, grade and worse outcomes after radical cystectomy, suggesting a role in bladder squamous cell carcinoma progression. Our findings support the need for further evaluation of cyclooxygenase-2 and inflammatory signaling pathways, and cyclooxygenase-2 targeted prevention or therapy in patients with bladder squamous cell carcinoma.

Tailoring treatment of rectal adenocarcinoma: Immunohistochemistry for predictive biomarkers

Over the past couple of decades, multimodality treatment for the management of resectable rectal cancer has substantially improved the outcome of affected patients. However, the broad and unpredictable response to tumor of patients with rectal cancer treated with preoperative chemoradiotherapeutic interventions shows that our understanding of the molecular events leading to radioresistance in patients affected with this malignancy remains sparse. Multiple attempts by individual molecular markers in gene array and tissue microarray studies have emerged with the goal of identifying predictors of a response to chemoradiation in patients with rectal cancer. In this report, we discuss the status of the markers currently available in an attempt to tailor specific targeted therapies for rectal cancer in the neoadjuvant setting.

Immunohistochemical expression of neural cell adhesion molecule in wilms tumors, nephrogenic rests, and fetal and postnatal renal cortices

Neural cell adhesion molecule (NCAM) has been suggested to be a marker for stem cells and progenitor cells in human fetal kidney and Wilms tumors. In this tissue microarray-based immunohistochemical study, we confirmed the expression of NCAM in Wilms tumors, nephrogenic rests, and metanephric mesenchyme and its early derivatives in fetal renal cortex. Neural cell adhesion molecule expression was noted in both favorable-histology and unfavorable-histology Wilms tumors. This indicates that NCAM may be an attractive therapeutic target in chemoresistant, high-risk Wilms tumors. In addition, we saw rare NCAM-positive interstitial stromal cells in postnatal kidney. It is not known if these persistent NCAM-positive interstitial cells might give rise to adult Wilms tumors and cases of pediatric Wilms tumors not associated with nephrogenic rests.