There are approximately 360,000 new cases of bladder cancer diagnosed globally each year. In addition, this disease is responsible for 145,000 deaths annually (Parkin et al 2005). Treatments for this cancer range from transurethral resection of the bladder tumor (TURBT) for low stage, non-invasive tumors, to the more drastic option of radical cystectomy with pelvic lymph node dissection for those tumors that are found to have invaded into the muscularis propria (Parekh et al 2006). Currently, the standard of care for diagnosing bladder cancer involves a combination of flexible cystoscopy and urine cytology, which is usually performed after the patient presents with episodes of gross hematuria. Following these evaluations, if evidence exists that warrants further investigation for bladder cancer a TURBT is performed and accurate staging and grading of the tumor can occur (O'Sullivan et al 2012). For those patients who have localized disease and have bladder preservation therapies, long term surveillance (in high grade disease this is life-long) is required to monitor for recurrence of tumor (Sylvester et al 2006). While cystoscopy has proven to be an accurate tool (sensitivity 80%) in the surveillance of bladder cancer, it is nonetheless a highly invasive procedure (Jocham et al 2008). In addition, urine cytology, which has served as the traditional adjunct to cystoscopy operates with a modest degree of sensitivity and therefore potential to deliver false negatives where malignant cells are not seen and false positives for bladder cancer in patients with an acute or chronically inflamed urothlelium (Grossman et al 2005). This leaves room for the development of a diagnostic test that is able to deliver results with the specificity of cystoscopy but without the potential for false negatives seen with urine cytology.

Recently, studies have shown that certain genetic markers exist that accompany the occurrence of bladder cancer and can accurately discriminate between bladder tumors and normal tissue. These genetic markers also show promise in being able to deliver additional information regarding the disease state of this cancer, such the stage and grade of the tumor (Dyrskjot et al 2003; Dyrskjot et al 2005; Thykjaer et al 2001). The informative nature of these mRNA expression profiles, along with the frequency with which tumor exfoliation into the urine occurs, has led to the development of a urine-based test that has the potential to diagnose and stratify bladder cancer. This urine test, known as Cxbladder Monitor, was developed by Pacific Edge Limited and is able to perform a combinatory analysis of the expression profiles of five genetic biomarkers (IGF, HOXA, MDK, CDC and IL8R gene expression) and two clinical variables (whether the previous tumor was primary or recurrent and the time since the previous tumor was resected). This test has the potential, with further testing, to produce a consolidated diagnostic score that is able to accurately risk stratify a given patient for recurrence of bladder cancer based on tumor characteristics. The five genetic markers include CDC2 (a gene involved in cell cycle activity and DNA synthesis) (O'Sullivan et al 2012), HOXA13 (transcription factor involved in morphogenesis and differentiation of the genitourinary tract) (Scott et al 2005), IGFBP5 (affects processes such as such as development, differentiation, and cellular survival) (Beattie et al 2006), MDK (a heparin binding growth factor expressed during embryogenesis) (Kadomatsu et al 2004), and CXCR2 which is expressed in neutrophils and is increased in non-malignant, inflammatory conditions. This marker is essential as it is helpful in reducing the risk of false positive results in patients with an inflamed urothelium (O'Sullivan et al 2012). The Cxbladder test is able to take into account the expression of all these relevant genetic markers and analyze their expression profiles and interactions via a 2 way linear discriminate algorithm to form a score that is able to predict the recurrence of bladder cancer. The success of these preliminary studies with Cxbladder show that it has a strong potential to be used as a alternate to urine cytology and challenge cytology's routine accompaniment to cystoscopy. More importantly, the use of Cxbladder in the surveillance patient has the potential to decrease the frequency with which cystoscopy would need to be performed, adjudicate equivocal cystoscopy and cytology atypia.