Altered myocyte contractility and calcium homeostasis in alpha-myosin heavy chain point mutations linked to familial dilated cardiomyopathy.

Mutations in the human cardiac motor protein beta-myosin heavy chain (ßMHC) have been long recognized as a cause of familial hypertrophic cardiomyopathy. Recently, mutations (P830L and A1004S) in the less abundant but faster isoform alpha-myosin heavy chain (αMHC) have been linked to dilated cardiomyopathy (DCM). In this study, we sought to determine the cellular contractile phenotype associated with these point mutations. Ventricular myocytes were isolated from 2 month male Sprague Dawley rats. Cells were cultured in M199 media and infected with recombinant adenovirus containing the P830L or the A1004S mutant human αMHC at a MOI of 500 for 18 h. Uninfected cells (UI), human ßMHC (MOI 500, 18 h), and human αMHC (MOI 500, 18 h) were used as controls. Cells were loaded with fura-2 (1 µM, 15 min) after 48 h. Sarcomere shortening and calcium transients were recorded in CO2 buffered M199 media (36°±1 C) with and without 10 nM isoproterenol (Iso). The A1004S mutation resulted in decreased peak sarcomere shortening while P830L demonstrated near normal shortening kinetics at baseline. In the presence of Iso, the A1004S sarcomere shortening was identical to the ßMHC shortening while the P830L was identical to the αMHC control. All experimental groups had identical calcium transients. Despite a shared association with DCM, the P830L and A1004S αMHC mutations alter myocyte contractility in completely different ways while at the same preserving peak intracellular calcium.

Hypoxia-inducible factor 1 alpha in clear cell renal cell carcinoma.

PURPOSE: Hypoxia-inducible factor-1 alpha (HIF-1 alpha) plays an important role in tumoral adaptation to hypoxic conditions by serving as a transcription factor for several crucial proteins, including vascular endothelial growth factor and carbonic anhydrase IX (CAIX). Here, we evaluated the significance of HIF-1 alpha in renal cell carcinoma (RCC). EXPERIMENTAL DESIGN: Immunohistochemical analysis was done on a tissue microarray constructed from paraffin-embedded primary tumor specimens from 357 patients treated by nephrectomy for RCC. Nuclear expression was evaluated by a single pathologist who was blinded to outcome. The expression levels were associated with pathologic variables and survival. RESULTS: HIF-1 alpha expression was greater in RCC than in benign tissue. Clear cell RCC showed the highest expression levels. In clear cell RCC, HIF-1 alpha was significantly correlated with markers of apoptosis (p21, p53), the mammalian target of rapamycin pathway (pAkt, p27), CXCR3, and proteins of the vascular endothelial growth factor family. HIF-1 alpha was correlated with CAIX and CAXII in localized, but not in metastatic RCC. HIF-1 alpha expression predicted outcome in metastatic patients: patients with high HIF-1 alpha expression (>35%) had significantly worse survival than patients with low expression (< or =35%); median survival, 13.5 versus 24.4 months, respectively (P = 0.005). Multivariate analysis retained HIF-1 alpha and CAIX expression as the strongest independent prognostic factors for patients with metastatic clear cell RCC. CONCLUSIONS: HIF-1 alpha is an important independent prognostic factor for patients with metastatic clear cell RCC. Because HIF-1 alpha and CAIX are independently and differentially regulated in metastatic clear cell RCC, both tumor markers can be complementary in predicting prognosis.

Prognostic factors for renal cell carcinoma with tumor thrombus extension.

PURPOSE: We identified prognostic factors for renal cell carcinoma with tumor thrombus extension and assessed whether the current T3 classification could be improved. MATERIALS AND METHODS: We studied clinicopathological parameters in 321 consecutive patients who were surgically treated for renal cell carcinoma with tumor thrombus extension. Disease specific survival was evaluated with univariate and multivariate analysis. Harrell's C-index was used to assess the prognostic accuracy of prognostic models. RESULTS: Tumor thrombus extended into the renal vein in 166 patients, the inferior vena cava in 137 and the atrium in 18. Metastatic renal cell carcinoma was found in 198 patients (62%). The thrombus level had no impact on clinicopathological parameters or survival but perioperative morbidity and mortality increased with cranial extension of the thrombus. Mean followup was 49 months. Five and 10-year disease specific survival rates were 36% and 24%, respectively. On multivariate analysis Eastern Cooperative Oncology Group performance status, lymph node and distant metastases, sarcomatoid features and perinephric fat invasion were independent prognostic factors. Weight loss, anemia, collecting system invasion, incomplete surgical resection, nuclear grade and T classification were also significant prognosticators on univariate analysis. For patients with advanced disease the number of metastatic sites and the disease-free interval further predicted prognosis. The overall immunotherapy response rate was 19%, which decreased with cranial extension of the thrombus. Redefinition of the T3 classification with the incorporation of fat invasion improved prognostic accuracy, as shown by an increase in the C-index. CONCLUSIONS: Eastern Cooperative Oncology Group performance status, metastatic status, sarcomatoid features and concomitant perinephric fat invasion are the most powerful prognostic factors of survival in renal cell carcinoma with tumor thrombus extension. Our data indicate that a redefinition of the current T3 classification may improve its predictive accuracy. We propose that T3 renal cell carcinoma with fat invasion or thrombus extension alone should be classified as T3a, while that with thrombus extension plus fat invasion should be classified as T3b.

Understanding the natural biology of kidney cancer: implications for targeted cancer therapy.

During the past several decades, there has been a significant increase in the understanding of the biology, clinical behavior, and prognostic factors of renal cell carcinoma (RCC). Such progress has led to greater sophistication in the diagnosis and classification of RCC. Here, we review recent advances in our knowledge of the biologic characteristics of RCC that have resulted in notable achievements in staging, prognosis, patient selection, and treatment.

Prognostic impact of tumor size on pT2 renal cell carcinoma: an international multicenter experience.

PURPOSE: The current tumor classification for renal cell carcinoma classifies pT2 tumors as larger than 7 cm in greatest dimension and limited to the kidney. We examined the current pT2 tumor classification of renal cell carcinoma and determined whether a tumor size cutoff exists that would improve prognostic accuracy. MATERIALS AND METHODS: We studied 706 patients with pT2 renal cell carcinoma treated with surgical extirpation at 9 international academic centers. Data collected from each patient included age at diagnosis, gender, 2002 TNM (tumor, node, metastasis) stage, tumor size, nuclear grade, performance status, histological subtype and disease specific survival. Disease specific survival was evaluated with univariate and multivariate analysis. RESULTS: Median followup was 52 months. Univariate Cox regression analysis showed a significant association of tumor size with disease specific survival (HR 1.11, p<0.001). An ideal tumor size cutoff of 11 cm was identified, which led to the stratification of 2 groups with respect to disease specific survival (p<0.0001) with 5 and 10-year survival rates of 73% and 65% for pT2 11 cm or less, and 57% and 49% for pT2 larger than 11 cm, respectively. The incidence of metastases was significantly greater in the larger than 11 cm group, while Eastern Cooperative Oncology Group performance status, Fuhrman grade and histological subtype were similar. Multivariate Cox regression analysis retained tumor size as an independent prognostic factor and as the strongest prognostic factor for patients with pT2N0M0 disease. CONCLUSIONS: Our data suggest that the current pT2 classification can be improved by subclassification into pT2a and pT2b based on a tumor size cutoff of 11 cm. Patients in the proposed pT2bN0M0 group are at higher risk for death from renal cell carcinoma and should be considered for adjuvant therapies. External validation is warranted before suggesting change to the TNM classification.

Clinicopathological features and prognosis of synchronous bilateral renal cell carcinoma: an international multicentre experience.

OBJECTIVE: To present a multicentre experience and the largest cohort to date of nonmetastatic (N0M0) synchronous bilateral renal cell carcinoma (RCC), as because it is rare the single-institutional experience is limited. PATIENTS AND METHODS: We retrospectively studied 10 337 patients from 12 urological centres to identify patients with N0M0 synchronous bilateral RCC; the clinicopathological features and cancer-specific survival were compared to a cohort treated for N0M0 unilateral RCC. RESULTS: In all, 153 patients had synchronous bilateral solid renal tumours, of whom 135 (88%) had synchronous bilateral RCC, 118 with nonmetastatic disease; 91% had nonfamilial bilateral RCC. Bilateral clear cell RCC was the major histological subtype (76%), and papillary RCC was the next most frequent (19%). Multifocality was found in 54% of bilateral RCCs. Compared with unilateral RCC, patients did not differ in Eastern Cooperative Oncology Group performance status (ECOG PS) and T classification, but bilateral RCCs were more frequently multifocal (54% vs 16%, P < 0.001) and of the papillary subtype (19% vs 12%), and less frequently clear cell RCC (76% vs 83%, P = 0.005). For the outcome, patients with nonmetastatic synchronous bilateral RCC and unilateral RCC had a similar prognosis (P = 0.63); multifocality did not affect survival (P = 0.60). Multivariate analysis identified ECOG PS, T classification, and Fuhrman grade, but not laterality, as independent prognostic factors for cancer-specific survival. CONCLUSIONS: Patients with N0M0 synchronous bilateral RCC and N0M0 unilateral RCC have a similar prognosis. The frequency of a familial history for RCC (von Hippel-Lindau disease or familial RCC) was significantly greater in bilateral synchronous than in unilateral RCC. The significant pathological findings in synchronous bilateral RCC are papillary subtype and multifocality.