Tamoxifen has been the mainstay of hormonal therapy in both early and advanced breast cancer patients for approximately three decades. The availability of novel compounds such as aromatase inhibitors (AIs) and fulvestrant, with different mechanism of action, is changing the scenario of endocrine treatment of postmenopausal breast cancer patients. In this review article, we have summarized the current knowledge of the mechanisms of resistance to endocrine therapy, in order to derive information that might be useful for therapeutic intervention. We propose that resistance to endocrine therapy is a progressive, step-wise phenomenon induced by the selective pressure of hormonal agents, which leads breast cancer cells from an estrogen-dependent, responsive to endocrine manipulation phenotype to a non-responsive phenotype, and eventually to an estrogen-independent phenotype. In particular, evidence suggests for each ‘action’ introduced to block estrogen stimulation of breast cancer cells (i.e. treatment with anti-estrogen), there are one or more corresponding ‘reactions’ that tumor cells can use to escape our attempts to block their growth: estrogen hypersensitivity associated with increased transcriptional activity of estrogen receptor α (ERα) and/or increased non-genomic activity of ERα, estrogen supersensitivity, increased growth factor signaling, suppression of ERα expression and finally estrogen independence. Activation of growth factor signaling is involved in each step of this phenomenon, and might ultimately substitute estrogen in sustaining the growth and the survival of breast cancer cells. In this respect, results of pre-clinical and clinical studies with AIs, fulvestrant and signaling inhibitors sustain this hypothesis. More importantly, the knowledge of the mechanisms involved in the resistance of breast cancer cells to endocrine therapy offers potential for novel therapeutic strategies.
Nicola Normanno, Massimo Di Maio, Ermelinda De Maio, Antonella De Luca, Andrea de Matteis, Antonio Giordano, and Francesco Perrone
Fabio Turco, Marcello Tucci, Rosario Francesco Di Stefano, Alessandro Samuelly, Maristella Bungaro, Marco Audisio, Chiara Pisano, Massimo Di Maio, Giorgio Vittorio Scagliotti, and Consuelo Buttigliero
Obesity represents a well-known risk factor for renal cell carcinoma development. Several studies evaluated the relationship between obesity and outcome in patients with non-metastatic and metastatic renal cell carcinoma using different parameters such as BMI, visceral fat area and s.c. fat area. These studies suggest that obesity is associated with a better prognosis in renal cell carcinoma patients. This phenomenon is called obesity paradox and it was found in other diseases in which obesity represents an established risk factor such as heart failure, diabetes, atrial fibrillation, hypertension and coronary heart disease. The purpose of this review is to analyze the mechanisms by which obesity increases the risk of renal cell carcinoma development, to describe the evidence available to date about the link obesity-outcome and to evaluate the mechanisms to explain this apparently paradoxical relationship.
Gianmarco Leone, Marcello Tucci, Consuelo Buttigliero, Clizia Zichi, Daniele Pignataro, Paolo Bironzo, Francesca Vignani, Giorgio V Scagliotti, and Massimo Di Maio
Antiandrogen withdrawal syndrome is an unpredictable event diagnosed in patients with hormone-sensitive prostate cancer treated with combined androgen blockade therapy. It is defined by prostate-specific antigen value reduction, occasionally associated with a radiological response, that occurs 4–6 weeks after first-generation antiandrogen therapy discontinuation. New-generation hormonal therapies, such as enzalutamide and abiraterone acetate, improved the overall survival in patients with metastatic castration-resistant prostate cancer, and recent trials have also shown the efficacy of abiraterone in hormone-sensitive disease. In the last few years, several case reports and retrospective studies suggested that the withdrawal syndrome may also occur with these new drugs. This review summarizes literature data and hypothesis about the biological rationale underlying the syndrome and its potential clinical relevance, focusing mainly on new-generation hormonal therapies. Several in vitro studies suggest that androgen receptor gain-of-function mutations are involved in this syndrome, shifting the antiandrogen activity from antagonist to agonist. Several different drug-specific point mutations have been reported. The association of the withdrawal syndrome for enzalutamide and abiraterone needs confirmation by additional investigations. However, new-generation hormonal therapies being increasingly used in all stages of disease, more patients may experience the syndrome when stopping the treatment at the time of disease progression, although the clinical relevance of this phenomenon in the management of metastatic castration-resistant prostate cancer remains to be defined.