Amira El-Sherif

The RNA-binding and adaptor protein Sam68 modulates signal-dependent splicing and transcriptional activity of the androgen receptor

The RNA‐binding protein Sam68 has been reported to be up‐regulated in clinical cases of prostate cancer (PCa), where it is thought to contribute to cell proliferation and survival. Consistent with this, we observed over‐expression of Sam68 in a panel of clinical prostate tumours as compared with benign controls. Since Sam68 is implicated in a number of signalling pathways, we reasoned that its role in PCa may involve modulation of the androgen receptor (AR) signalling cascade, which drives the onset and progression of PCa. We found that Sam68 interacts with the AR in vivo in LNCaP cells, and is dynamically recruited to androgen response elements within the promoter region of the prostate‐specific antigen (PSA) gene. Based on its known functions and nuclear location, Sam68 might either: (a) co‐regulate AR‐dependent transcription positively or negatively; or (b) modulate AR‐dependent alternative splicing by enhancing incorporation of a Sam68‐responsive exon transcribed under the control of an androgen‐responsive promoter. We tested these possibilities using functional assays. Both wild‐type Sam68 protein and the Sam68V229F mutant, which is impaired in RNA binding, functioned as a ligand‐dependent AR co‐activator on an androgen‐regulated reporter gene. In contrast, splicing of a Sam68‐responsive variable exon, transcribed under control of an androgen‐responsive promoter, was strongly repressed in the presence of AR and androgens. This splicing inhibition was reversed by ectopic expression of Sam68 but enhanced by Sam68V229F. These results demonstrate that Sam68 has separable effects on AR‐regulated transcriptional activity and alternative splicing, both of which may affect PCa phenotypes. Copyright

Regulation of gene expression by the RNA-binding protein Sam68 in cancer

Sam68 (Src-associated in mitosis 68 kDa) is the prototypical member of the STAR (signal transducer and activator of RNA) family of RNA-binding proteins. Sam68 is implicated in a number of cellular processes including signal transduction, transcription, RNA metabolism, cell cycle regulation and apoptosis. In the present review, we summarize the functions of Sam68 as a transcriptional and post-transcriptional regulator of gene expression, with particular relevance to cancer.

Side Population in Human Non-Muscle Invasive Bladder Cancer Enriches for Cancer Stem Cells That Are Maintained by MAPK Signalling

Side population (SP) and ABC transporter expression enrich for stem cells in numerous tissues. We explored if this phenotype characterised human bladder cancer stem cells (CSCs) and attempted to identify regulatory mechanisms. Focusing on non-muscle invasive bladder cancer (NMIBC), multiple human cell lines were used to characterise SP and ABC transporter expression. In vitro and in vivo phenotypic and functional assessments of CSC behaviour were undertaken. Expression of putative CSC marker ABCG2 was assessed in clinical NMIBC samples (n = 148), and a role for MAPK signalling, a central mechanism of bladder tumourigenesis, was investigated. Results showed that the ABCG2 transporter was predominantly expressed and was up-regulated in the SP fraction by 3-fold (ABCG2hi) relative to the non-SP (NSP) fraction (ABCG2low). ABCG2hi SP cells displayed enrichment of stem cell markers (Nanog, Notch1 and SOX2) and a three-fold increase in colony forming efficiency (CFE) in comparison to ABCG2low NSP cells. In vivo, ABCG2hi SP cells enriched for tumour growth compared with ABCG2low NSP cells, consistent with CSCs. pERK was constitutively active in ABCG2hi SP cells and MEK inhibition also inhibited the ABCG2hi SP phenotype and significantly suppressed CFE. Furthermore, on examining clinical NMIBC samples, ABCG2 expression correlated with increased recurrence and decreased progression free survival. Additionally, pERK expression also correlated with decreased progression free survival, whilst a positive correlation was further demonstrated between ABCG2 and pERK expression. In conclusion, we confirm ABCG2hi SP enriches for CSCs in human NMIBC and MAPK/ERK pathway is a suitable therapeutic target.

Accuracy of the revised 2010 TNM classification in predicting the prognosis of patients treated for renal cell cancer in the north east of England

Background The TNM classification for renal cell cancer (RCC) should accurately predict and assign prognostic information for patients. In this study the recent 2010 revision to the TNM classification was compared with the previous 2002 classification with regard to survival outcomes. Methods All patients having radical nephrectomy for RCC in the 5-year period 2004–8 at a tertiary referral centre were included. Pathological and radiological records were reviewed to identify TNM stage (2002 and 2010 classification) and survival data were captured. Results 345 patients with RCC were identified. Based on the 2002 TNM staging system and using outcomes in T1 staged tumours as a baseline, statistically significant differences in disease-specific survival were noted between patients with T1 and T3b tumours (log rank p<0.001) but not between those with T1 and T3a tumours (p=0.33). However, when tumour stage was reassigned according to the 2010 classification, patients with T3a tumours were also found to do statistically worse than T1 staged disease (p<0.001). Conclusion In our cohort, the new 2010 TNM reclassification of T3 tumours showed better correlation with predicting worsening outcomes compared with localised disease.

Twenty-nine Leydig cell tumors: Histological features, outcomes and implications for management

Leydig cell tumors are the most common interstitial neoplasm of the testes. Metastatic progression is historically quoted at over 10%, fuelling uncertainty as to the safety of testis sparing surgery. Between June 1998 and March 2009, 29 patients underwent surgery for Leydig cell tumor of the testis in our cancer network. We reviewed their histological features and clinical outcomes. Four patients with sub‐5 millimetre lesions underwent testis sparing surgery and 25 were treated with radical orchidectomy. Histopathological characteristics that have been linked with risk of malignant progression were seen infrequently in our cohort: diameter greater than 50 mm, 0%; nuclear atypia, 14%; >3 mitoses per 10 high‐power fields, 3%; infiltrative borders, 10%; necrosis, 3%; and vascular invasion 0%. No patient developed local or distant recurrent disease over a median follow up of 49 months, including seven and four patients disease‐free at 5 and 10 years, respectively. The rate of metastatic progression is likely to be significantly less than 10%. Our data suggest that, in the absence of high‐risk histopathological features, this tumor can be safely regarded as benign, pending a longer‐term follow‐up evaluation.

The Role of Early Re-Resection in pTaG3 Transitional Cell Carcinoma of the Urinary Bladder

Aim: The clinical outcome and optimal treatment methodology for pTaG3 transitional cell carcinoma (TCC) of the urinary bladder remains controversial. We retrospectively evaluate the clinical behaviour and final outcome of 64 patients diagnosed with primary pTaG3 TCC bladder and evaluate the role of early re-resection following initial diagnosis. Patients and methods: Between January 2000 and December 2008, 64 patients were diagnosed with primary pTaG3 TCC of the urinary bladder at our institution. Following a careful retrospective review of their medical records, clinical parameters including patient age, gender, tumour morphology, operating surgeons experience and adjuvant therapies were entered into a database. The outcome of re-resection, recurrence rate, progression and overall survival were recorded. All patients had their upper tracts screened with an ultrasound and intravenous urogram (IVU). Results: The mean age at time of diagnosis was 78 years (range 59–98). Seventy seven percent (49) of patients underwent an early re-resection (group 1). Residual tumour was identified in 49% (24) patients and the incidence of tumour upstaging was 10% (7). At re-resection 3% (2) of patients were found to have muscle-invasive disease. Twenty three percent (15) of patients did not have an early re-resection (group 2). There was a significant reduction in the incidence of recurrent TCC in group 1 in comparison to group 2 (5% vs. 62%) [p < 0.05]. At a mean follow up of 48.9 months (range 12–124), 48 patients (75%) were alive; 25% (16) of patients had died of causes unrelated to bladder cancer. Disease-specific survival in both groups was 100%. Conclusion: pTaG3 TCC of the urinary bladder shows a variable clinical course and early re-resection significantly reduces the risk of recurrence. We strongly recommend treatment with early re-resection and subsequent treatment as per histology at re-resection. All patients with primary pTaG3 TCC of the urinary bladder should be followed up with further close surveillance using a strict follow up as these patients have a potential for disease progression.

Comparison of examination of the entire uterine cervix with routine cervical sampling in hysterectomy specimens from women with endometrial cancer

Background: Cervical involvement by endometrial cancer alters the FIGO stage and determines clinical management, but there are no accepted guidelines for cervical sampling of these cases. Aim: To assess whether sampling more than two “routine” blocks of the cervix (anterior and posterior) alters the pathological staging of hysterectomy specimens for endometrial cancer. Methods: Histological involvement of the cervix was prospectively compared in hysterectomies performed for proven endometrial cancer (n = 61). Specimens had two “routine” blocks taken from anterior and posterior cervix; all of the remaining cervix was also processed for histological assessment. Results: 61 cases of endometrial cancer had the entire uterine cervix processed. There were 54 cases of endometrioid adenocarcinoma and 7 special types. Twelve cases had cervical involvement (stage 2A or 2B), and seven cases were stage 3A or above, of which three also had cervical involvement. In none of the 61 cases did the additional cervical blocks (n = 544) taken alter the staging made on the “routine” blocks. Conclusion: Sampling of two blocks from the cervix appears sufficient for histological staging of endometrial cancer in hysterectomy specimens.

Can the Kattan nomogram still accurately predict prognosis in renal cell carcinoma using the revised 2010 tumor-nodes-metastasis reclassification?

The Kattan nomogram has been used in renal cell cancer to predict progression‐free survival after nephrectomy. Tumor–nodes–metastasis staging is essential for the calculation of this score. The effect of the recent 2010 revision to the tumor–nodes–metastasis classification on the predictive ability of the Kattan nomogram was studied. All patients having radical nephrectomy for renal cell cancer in the 5‐year period of 2004–2008 at a tertiary referral center were included. Pathological and radiological records were reviewed to identify tumor–nodes–metastasis stage (2002 and 2010 classifications). Kattan scores were calculated for the 2002 and 2010 tumor–nodes–metastasis stages, and the effect on survival predictions were compared with actual outcomes. A total of 291 patients with non‐metastatic renal cell cancer were identified. Revision of the tumor–nodes–metastasis staging from the 2002 to 2010 classification resulted in an increase in the number of patients with stage pT3a (from 30 to 75), a reduction in the patients with stage pT3b (from 57 to 10) and a small increase in stage pT4 cases (1 to 3). This altered the proportion of patients in the Kattan prognostic of “good” (from 61% to 69%), “intermediate” (from 29% to 22%) and “poor” (from 10% to 8%). The overall median predicted 5‐year progression‐free survival was 79.8% with 2002 tumor–nodes–metastasis, and 81.8% with 2010 tumor–nodes–metastasis. Actual 5‐year progression‐free survival was 83.0%, which was not significantly different from that predicted using either tumor–nodes–metastasis classification (P = 0.66). On comparing the new 2010 and old 2002 tumor–nodes–metastasis classification in our cohort, we showed the predictive ability of the Kattan nomogram remained unaltered.

Carcinoid tumour in an ileocystoplasty: A reminder to consider native bowel disease in the reconstructed urinary tract

n 1992 a 73-year-old woman underwent subtoal cystectomy and ileocystoplasty for refractory nterstitial cystitis. In 2004 cystoscopic surveillance etected a five millimetre polypoid lesion with a auliflower-like appearance at the centre of the clam’ segment. A pinch biopsy was sent for analyis. Cross-sectional imaging suggested thickening f the ‘clam’ segment and involvement of he perivesical fat, but there were no distant etastases and urinary 24-h 5-HIAA levels (a etabolite of serotonin which may be elevated

Importance of local data on occurrence and outcomes of renal cell cancer

Background: In comparatively socioeconomically deprived areas male cancer mortality is often above the national average. Given this, we explored the pattern of presentation and outcomes of men with conventional clear cell renal cell carcinoma (CCRCC) undergoing nephrectomy at a North East of England regional tertiary referral centre. Patients and methods: A retrospective review of CCRCC patients treated with nephrectomy between 2004 and 2008 was performed. Risk of progression for men and women was calculated using Mayo, Memorial Sloan-Kettering (MSK) and Kattan prognostic scores. Outcomes of disease free progression and overall survival were measured. Results: 292 patients with complete local follow up were identified that had undergone radical nephrectomy for conventional clear cell histology. The median (range) follow up was 36 months (10–65 months), and men accounted for 64% of these cases. At presentation, 45% of cases presented with stage III–IV (>T2, N0/1, M0/1) disease compared with 32% nationally (BAUS cancer registry). At diagnosis men had more advanced tumours compared with women (54% vs. 22% for stage >T2, N0/1, M0/1; p < 0.001) and had higher risk of progression based on prognostic scores (p < 0.01) despite similar risk factors and clinical symptoms. Early outcome analysis comparing men to women revealed both lower disease-free survival (82% vs. 89%) and overall survival (87% vs. 93%) in men at 24 months (p < 0.01). However, stage for stage comparisons between men and women demonstrated no significant difference in survival. Discussion: Men in the North East of England presented later with more advanced CCRCC. The reason for this remained undefined in this study. This pattern is consistent with reports of adverse male cancer-related outcomes in deprived areas and highlights the importance of local data in planning local health care.