Role of MGMT as biomarker in colorectal cancer

O6-methylguanine DNA methyltransferase(MGMT) gene promoter methylation plays an important role in colorectal carcinogenesis, occurring in about 30%-40% of metastatic colorectal cancer. Its prognostic role has not been defined yet, but loss of expression of MGMT, which is secondary to gene promoter methylation, results in an interesting high response to alkylating agents such as dacarbazine and temozolomide. In a phase 2 study on heavily pre-treated patients with MGMT methylated metastatic colorectal cancer, temozolomide achieved about 30% of disease control rate. Activating mutations of RAS or BRAF genes as well as mismatch repair deficiency may represent mechanisms of resistance to alkylating agents, but a dose-dense schedule of temozolomide may potentially restore sensitivity in RAS-mutant patients. Further development of temozolomide in MGMT methylated colorectal cancer includes investigation of synergic combinations with other agents such as fluoropyrimidines and research for additional biomarkers, in order to better define the role of temozolomide in the treatment of individual patients.

One size does not fit all for pancreatic cancers: A review on rare histologies and therapeutic approaches

Exocrine pancreatic neoplasms represent up to 95%of pancreatic cancers(PCs)and are widely recognized among the most lethal solid cancers,with a very poor 5-year survival rate of 5%-10%.The remaining<5%of PCs are neuroendocrine tumors that are usually characterized by a better prognosis,with a median overall survival of 3.6 years.The most common type of PC is pancreatic ductal adenocarcinoma(PDAC),which accounts for roughly 85%of all exocrine PCs.However up to 10%of exocrine PCs have rare histotypes,which are still poorly understood.These subtypes can be distinguished from PDAC in terms of pathology,imaging,clinical presentation and prognosis.Additionally,due to their rarity,any knowledge regarding these specific histotypes is mostly based on case reports and a small series of retrospective analyses.Therefore,treatment strategies are generally deduced from those used for PDAC,even if these patients are often excluded or not clearly represented in clinical trials for PDAC.For these reasons,it is essential to collect as much information as possible on the management of PC,as assimilating it with PDAC may lead to the potential mistreatment of these patients.Here,we report the most significant literature regarding the epidemiology,typical presentation,possible treatment strategies,and prognosis of the most relevant histotypes among rare PCs.

Future Directions in Metastatic Castration Resistant Prostate Cancer (mCRPC): Clinical Rationale and Use of New-Generation Hormonal Therapies

Several recent studies in mCRPC have identified the mechanisms of tumoral growth after the disease becomes unresponsive to standard hormonal therapy. These studies have highlighted the importance of residual intratumoral androgens in maintaining androgen receptor (AR) transcriptional activity in mCRPC [1]. Based on this findings, it has been possible to develop drugs, blocking the key enzyme in the biosynthesis of androgens through the inhibition of cytochrome p450 17 (CYP17) such as Abiraterone Acetate (AA) and drugs which directly target the AR including Enzalutamide (E) and Orteronel. Before this new knowledge, mCRPC treatment benefited from chemotherapy with taxanes. Recently a new taxane, Cabazitaxel (C), was approved in second line setting in association with prednisone. Retrospective analyses have tried to clarify the current role of chemotherapy in mCRPC patients and the right chemotherapy sequence of use of chemotherapy compared to new hormonal agents. Moreover, it would be important to address changes in the endpoints used in clinical trials, based on the stage of disease including the presence tumor-related symptoms, in order to identify the right therapeutic strategy.

Update on Therapeutic Strategy in Lung Carcinoids

An estimated 25% to 30% of all neuroendocrine tumors (NETs) have their origin in the bronchial tree and into the lungs. Although lung NETs account for less than 1% of all pulmonary malignancies, the incidence of these neoplasms has risen precipitously since the mid 1970s. Currently, according to the 2004 World Health Organization categorization, these tumors are separated into 4 subtypes characterized by increasing biologic aggressiveness: low-grade typical carcinoid (TC), intermediate-grade atypical carcinoid (AC), high-grade large-cell neuroendocrine carcinoma (LCNEC) and small-cell carcinoma (SCLC). Surgery is the treatment of choice for typical and atypical carcinoid lung NETs with loco-regional disease. At diagnosis up to 64% of patients with atypical carcinoid lung NETs present with lymph node metastases, and 5-year survival ranges from 61% to 88%. In contrast, lymph node metastases are present in fewer than 15% of typical carcinoid lung NETs, and 5-year survival exceeds 90%. To date, there is no recognized standard of treatment for advanced carcinoid lung NETs. In recent years only two trials reported intriguing results regarding lung NETs: a phase 2 retrospective study of dacarbazine derivative temozolomide and the phase 3, RADIANT-2 trial in advanced NETs. Successful management requires a multidisciplinary team management. This review is restricted to typical/atypical NETs.

Orbital lesions,an exceedingly rare site of neuroendocrine tumor metastasis

Neuroendocrine tumors are rare neoplasms arising primarily in the gastrointestinal tract and lung.The liver is the most common site of metastases,but these tumors can rarely metastasize to atypical sites.Surgery is the only curative approach while the optimal medical treatment is debated.From this perspective,a multidisciplinary approach for each single case becomes very important.In this report we describe the case of a male affected by a single intraorbital metastasis from a midgut well differentiated neuroendocrine tumor.The patient refused surgical removal and therefore he was at first treated with stereotactic radiotherapy and systemic treatment with a somatostatin analog(SSA).After achieving a stable disease for four months he underwent primary tumor resection.Six years after the initial diagnosis,the patient is currently stable and receiving SSA at standard dose.