E-cadherin is expressed by many normal tissues and is the main mediator of cell-cell adhesion mediated by the cadherin cell adhesion molecules. Considering these actions on epithelial polarity it can be considered as a tumor suppressor. N-cadherin in normal condition is not expressed by epithelial tissues. In advanced cancers, tumor progressions or metastatic settings it is reported an increase in N-cadherin that is accompanied by a decrease in E-cadherin. This phenomena is known as cadherin switching (CS).
Our research will focus on bladder cancer and we'll analyze both tumor tissue samples and liquid biopsy samples (circulating tumor cells).
Patients with histologically confirmed diagnosis of bladder cancer will be divided in three groups in accordance with tumor characteristics: non-muscle invasive tumors (Ta-1 N0 M0), muscle invasive tumors (T2-4 N0 M0) and metastatic muscle invasive tumors (T2-4 N1-3 or M1).
Tumor tissue analysis: formalin-fixed, paraffin-embedded tumor samples will be used to evaluate DAPI, GATA3, E-cadherin and N-cadherin in tumor tissue.
Liquid biopsy analysis: peripheral blood will be collected at the time of patients enrollment and 1 hour before main surgery. First 3 mL of blood sample will be incubated with 4 mL of ScreenCell FC buffer, containing red blood cell lysis and fixation buffer; 30% NaOH will be added until a pH of around 7. Seven mL of diluted blood will be transferred into device tank and filtered using a vacutainer tube. After washing with 1.6 mL of PBS to remove red blood cells debris, the filter will be released on absorbing paper. The ScreenCell® Cyto filter is released into a standard microscopy glass slide and cytological/ immunocytochemical studies can be conducted directly on the filter using 4 markers: GATA3, DAPI, E-cadherin and N-cadherin.
Difference in these markers expression and cadherin switching will be reported and compared in accordance with different groups.
Although the precise timing of cadherin switching remains unclear and all the associated signaling pathways are unknown, it is a process that happens during the evolution of the disease and is important to establish exactly when. When the disease move to muscle invasion or later when metastatic spread begins?
Treating bladder cancer is a big challenge and current methods for predicting tumor recurrences, progressions and metastatic evolution are inadequate. Cadherin switching could be a new validated tool able to predict tumor behavior and to guide clinicians to perform the best treatment. To date we refer only to clinical and pathological informations and this is not sufficient for a good management of the disease. Cadehrin switching could be a crucial prognostic marker able to discriminate between a preserving approach such as transurethral resection of the bladder (TURB) followed by maintenance bacillus Calmette-Guerin (BCG) or an invasive approach like cystectomy. CS could be even important in planning chemotherapy. Which setting is more appropriate? Neoadjuvant or adjuvant? Which is the correct schedule and timing? Identifying genetic and molecular cancer alterations could help our knowledge, understanding and releasing new cancer treatments needed to address tumor microenvironment and continuously changing molecular defects in the tumor itself.
The impact on cancer and clinical relevance will be demonstrated by changing, in the future, bladder cancer therapeutic approach and developing new drugs able to act on new targets. New molecules capable to regulate cadherins expression could represent a strategy to block the progression of non-muscle invasive tumors to muscle invasion.
His potential to acquire leadership in bladder cancer field is confirmed by the increasing role of CTCs and liquid biopsy as a prognostic marker for risk stratification in patients with bladder cancer and to predict both recurrence and progression. As well it will be possible to better develop a tailor therapy for each patient at each phase of the disease after a better understanding of biological tumor behavior. This will have an important impact on bladder cancer therapy allowing an accurate decision making process between conservative and invasive approaches and between pharmacological adjuvant and neoadjuvant therapies.