Role of KIT expression in the prognosis of clear cell renal cell carcinomas in Chinese patients

Identification of genes and pathways leading to metastasis and poor prognosis in melanoma

Melanoma causes the highest mortality rate among all skin cancers. However, the underlying molecular mechanisms leading to metastasis and poor prognosis in melanoma have not been fully elucidated. In this study, the differentially expressed genes (DEGs) related to metastasis in melanoma were screened out. The results of gene annotation was combined with The Cancer Genome Atlas (TCGA) database. The microRNA (miRNA) network that regulates key genes and their correlation with BRAF^V600E was preliminarily analyzed. Cell and molecular biology experiments were conducted to verify the results of bioinformatics analysis. Results showed that the PI3K-Akt signaling pathway contained the key genes CDK2, CDK4, KIT, and Von Willebrand factor. Survival analysis showed that high expression of the four key genes significantly reduced the survival rate of patients with melanoma. Correlation analysis showed that BRAF^V600E may regulate the expression of the four key genes, and a total of 240 miRNAs may regulate this expression. Experiments showed that the inactivation of key genes inhibits the proliferation, migration, and invasion of melanoma. In conclusion, the PI3K-Akt signaling pathway and the four key genes promoted the proliferation, migration, and invasion of melanoma, and related to poor prognosis of patients with melanoma.

Immunohistochemical study of C-kit expression in subtypes of renal cell carcinoma

Objective

Renal cell carcinomas (RCCs) include about 2% of adult neoplasms and 90-95% of all renal tumors. Mostly, it is possible to distinguish RCC subtypes using hematoxylin-eosin staining. However, overlapping morphologic features cause some difficulties in making a precise diagnosis. In order to render an accurate diagnosis, additional methods such as immunohistochemical staining for c-kit have been recommended. In this study, we aimed to investigate c-kit gene expression in various subtypes of RCC.

Material and methods

We reviewed 65 diagnosed RCC cases. Formalin- fixed, paraffin- embedded specimens were available for the cases. The expression of c-kit was evaluated using immunohistochemistry. The correlation between c-kit expression and clinicopathological parameters including patients' age and gender in addition to grade, stage, and size of the tumor were investigated.

Results

Six cases of 39 clear cell types (15.4%), 8 of 13 papillary types (61.5%), 11 of 12 chromophobe types (91.7%), and no sarcomatoid type were positive for c-kit expression. Based on chi-square test results, there was a significant relationship between RCC subtypes and c-kit expression (p=0.001). There was no significant correlation between age, sex, grade, stage, and size of the tumor and c-kit expression.

Conclusion

The expression of c-kit in RCC may have diagnostic significance in subtypes of RCC especially papillary and chromophobe subtypes of RCC.

Analyses of Potential Predictive Markers and Response to Targeted Therapy in Patients with Advanced Clear-cell Renal Cell Carcinoma

Background:

Vascular endothelial growth factor-targeted agents are standard treatments in advanced clear-cell renal cell carcinoma (ccRCC), but biomarkers of activity are lacking. The aim of this study was to investigate the association of Von Hippel-Lindau (VHL) gene status, vascular endothelial growth factor receptor (VEGFR) or stem cell factor receptor (KIT) expression, and their relationships with characteristics and clinical outcome of advanced ccRCC.

Methods:

A total of 59 patients who received targeted treatment with sunitinib or pazopanib were evaluated for determination at Cancer Hospital and Institute, Chinese Academy of Medical Sciences between January 2010 and November 2012. Paraffin-embedded tumor samples were collected and status of the VHL gene and expression of VEGFR and KIT were determined by VHL sequence analysis and immunohistochemistry. Clinical-pathological features were collected and efficacy such as response rate and Median progression-free survival (PFS) and overall survival (OS) were calculated and then compared based on expression status. The Chi-square test, the Kaplan–Meier method, and the Lon-rank test were used for statistical analyses.

Results:

Of 59 patients, objective responses were observed in 28 patients (47.5%). The median PFS was 13.8 months and median OS was 39.9 months. There was an improved PFS in patients with the following clinical features: Male gender, number of metastatic sites 2 or less, VEGFR-2 positive or KIT positive. Eleven patients (18.6%) had evidence of VHL mutation, with an objective response rate of 45.5%, which showed no difference with patients with no VHL mutation (47.9%). VHL mutation status did not correlate with either overall response rate (P = 0.938) or PFS (P = 0.277). The PFS was 17.6 months and 22.2 months in VEGFR-2 positive patients and KIT positive patients, respectively, which was significantly longer than that of VEGFR-2 or KIT negative patients (P = 0.026 and P = 0.043).

Conclusion:

VHL mutation status could not predict the efficacy of sunitinib or pazopanib. Further investigation of VHL/VEGFR pathway components is needed.

c-KIT: potential predictive factor for the efficacy of sorafenib in metastatic renal cell carcinoma with sarcomatoid feature

BACKGROUND

Vascular endothelial growth factor-targeted therapy has been standard care for metastatic renal cell carcinoma for years. However, little clinical experience on these agents in the treatment of sarcomatoid tumors has been documented. The aim of the present study was to detect the expression of c-KIT in the primary tumor of metastatic renal cell carcinoma with sarcomatoid feature, and to reveal its potential value of predicting the efficacy of sorafenib treatment and survival of the patients.

PATIENTS AND METHODS

Seventeen patients were enrolled and treated with sorafenib as a second-line treatment after cytokine therapy. The expressions of c-KIT was tested immunohistochemically in the 17 specimens of primary renal tumors. The correlation between c-KIT status and treatment effect was compared. Univariate and multivariate analysis were employed to determine the survival difference between c-KIT-positive and c-KIT-negative patients.

RESULTS

Twelve of 17 specimens (70.6%) were detected to be overexpressing c-KIT. c-KIT positive patients had higher disease control rate (75%) compared with c-KIT-negative patients (25%), P = .036. Median overall survival time was 92 weeks for c-KIT positive patients and 44 weeks for c-KIT negative patients, log rank χ(2) = 9.566, P = .002. Multivariate Cox regression model analysis only revealed number of metastatic organs and c-KIT as independent prognostic factors.

CONCLUSION

Our findings suggest that c-KIT can be a potential predictive factor for metastatic renal cell carcinoma with sarcomatoid feature in treatment using sorafenib, and patients with positive c-KIT expression might have better responses and obtain longer overall survival time.

The role of surgery in the management of isolated metastases to the pancreas

Metastasectomy with curative intent has become standard practice for the management of some malignancies. Resection of isolated metastatic colorectal cancer, gastrointestinal stromal tumours, neuroendocrine cancers, renal-cell cancer and sarcoma is associated with longer survival or even cure. The strongest evidence in favour of metastasectomy exists for colorectal cancer, in which resection of limited metastatic disease in some patients is associated with 5-year survival rates of more than 50%.(1-3) High incidence of the disease, predictable tumour biology, and development of successful chemotherapies have encouraged metastasectomy. Furthermore, improved safety of complex surgeries over the past several decades has lowered the threshold for more aggressive surgical intervention. Most literature on metastasectomy pertains to the resection of disease involving the liver, lung, and brain. However, metastasectomy has been described for almost every organ system, including the pancreas. In this Review, we discuss resection of isolated cancer metastases to the pancreas. Pancreatic metastasectomy is most often done through a formal pancreatic resection such as pancreaticoduodenectomy or distal pancreatectomy. Less often, pancreatic metastasectomy is done by enucleation or a pancreas sparing operation such as a central pancreatectomy.