New insights into molecular mechanisms of sunitinib-associated side effects.

The introduction of targeted therapy represents a major advance in the treatment of tumor progression. Targeted agents are a novel therapeutic approach developed to disrupt different cellular signaling pathways. The tyrosine kinase inhibitor sunitinib specifically blocks multiple tyrosine kinase receptors that are involved in the progression of many tumors. Sunitinib is the current standard of care in first-line treatment of advanced renal cell carcinoma, and it is approved in imatinib-intolerant and imatinib-refractory gastrointestinal stromal tumors. However, it is increasingly evident that sunitinib may display collateral effects on other proteins beyond its main target receptors, eliciting undesirable and unexpected adverse events. A better understanding of the molecular mechanisms underlying these undesirable sunitinib-associated side effects will help physicians to maximize efficacy of sunitinib and minimize adverse events. Here, we focus on new insights into molecular mechanisms that may mediate sunitinib-associated adverse events.

Stem cell and lung cancer development: blaming the Wnt, Hh and Notch signalling pathway.

Primary lung cancer may arise from the central (bronchial) or peripheral (bronchiolo-alveolar) compartments. However the origins of the different histological types of primary lung cancer are not well understood. Stem cells are believed to be crucial players in tumour development and there is much interest in identifying those compartments that harbour stem cells involved in lung cancer. Although the role of stem cells in carcinogenesis is not well characterised, emerging evidence is providing new insights into this process. Numerous studies have indicated that lung cancer is not a result of a sudden transforming event but a multistep process in which a sequence of molecular changes result in genetic and morphological aberrations. The exact sequence of molecular events involved in lung carcinogenesis is not yet well understood, therefore deeper knowledge of the aberrant stem cell fate signalling pathway could be crucial in the development of new drugs against the advanced setting.

Molecular basis of hypertension side effects induced by sunitinib.

Over the past decade a number of vascular complications have emerged, such as newly developed or worsened hypertension, in patients who were administered with new cancer treatments for several types of cancer that were untreatable earlier. Hypertension is emerging as one of the most common adverse effects of therapy with angiogenesis inhibitors. Small-molecule inhibitors of vascular endothelial growth factor signalling are associated with a high proportion of patients with hypertension. The mechanisms underlying the development of hypertension are not well known, although there seem to be several mechanisms. Physiopathology of hypertension implicates abnormalities in endothelial function and angiogenesis. Several features of hypertensive patients are reduced number of arterioles and capillaries, alterations of the microvascular network, decrease in vascular wall compliance and flexibility, reduced nitric oxide bioactivity and increases in plasma vascular endothelial growth factor. Treatment with tyrosine kinase inhibitors (TKIs) is associated with a significant and sustained increase in blood pressure. We suspect that TKIs exert their hypertensive effects directly at the level of the microvascular network through processes such as vascular rarefaction, endothelial dysfunction and/or altered nitric oxide metabolism. This study shows the vascular complications of treatment with a TKI, sunitinib (SU11248), with special emphasis on hypertension.

Expression of Wnt gene family and frizzled receptors in head and neck squamous cell carcinomas.

Genes of the Wnt and Frizzled class, expressed in HNSCC tissue and cell lines, have an established role in cell morphogenesis and differentiation, and also they have oncogenic properties. We studied Wnt and Fz genes as potential tumor-associated markers in HNSCC by qPCR. Expression levels of Wnt and Fz genes in 22 unique frozen samples from HNSCC were measured. We also assessed possible correlation between the expression levels obtained in cancer samples in relation to clinicopathologic outcome. Wnt-1 was not expressed in the majority of the HNSCC studied, whereas Wnt-5A was the most strongly expressed by the malignant tumors. Wnt-10B expression levels were related with higher grade of undifferentiation. Related to Fz genes, Fz-5 showed more expression levels in no-affectation of regional lymph nodes. Kaplan-Meier survival analyses suggest a reduced time of survival for low and high expression of Wnt-7A and Fz-5 mRNA, respectively. qPCR demonstrated that HNSCC express Wnt and Fz members, and suggested that Wnt and Fz signaling is activated in HNSCC cells.

Origin of renal cell carcinomas.

Cancer is a heritable disorder of somatic cells: environment and heredity are both important in the carcinogenic process. The primal force is the "two hits" of Knudson's hypothesis, which has proved true for many tumours, including renal cell carcinoma. Knudson et al. [1, 2] recognised that familial forms of cancer might hold the key to the identification of important regulatory elements known as tumour-suppressor genes. Their observations (i.e., that retinoblastoma tend to be multifocal in familial cases and unifocal in sporadic presentation) led them to propose a two-hit theory of carcinogenesis. Furthermore, Knudson postulated that patients with the familial form of the cancer would be born with one mutant allele and that all cells in that organ or tissue would be at risk, accounting for early onset and the multifocal nature of the disease. In contrast, sporadic tumours would develop only if a mutation occurred in both alleles within the same cell, and, as each event would be expected to occur with low frequency, most tumours would develop late in life and in a unifocal manner [3, 4]. The kidney is affected in a variety of inherited cancer syndromes. For most of them, both the oncogene/tumour-suppressor gene involved and the respective germline mutations have been identified. Each of the inherited syndromes predisposes to distinct types of renal carcinoma. Families with hereditary predisposition to cancer continue to provide a unique opportunity for the identification and characterisation of genes involved in carcinogenesis. A surprising number of genetic syndromes predispose to the development of renal cell carcinoma, and genes associated with five of these syndromes have been already identified: VHL, MET, FH, BHD and HRPT2. Few cancers have as many different types of genetic predisposition as renal cancer, although to date only a small proportion of renal cell cancers can be explained by genetic predisposition.