Cytosystems' approach to transforming urine cytology is based on three ground-breaking technological developments:
1. The ability to rapidly prepare cytology-ready samples of urothelial cells from freshly voided urine samples collected at point of care (thus negating the in-transit sample degradation occurring in conventional urine cytology practices)
2. Highly sensitive and specific, patented monoclonal antibody technology
3. Improved cytological detection of malignancy through digital analysis.
Figure 1: Highly sensitive and specific, patented monoclonal antibody technology shown lighting up cancer cells (in pink, see example highlighted by arrow).
The MCM complex: the core of Cytosystems
The monoclonal antibody at the core of Cytosystems' assay is specific for minichromosome maintenance protein-2 (MCM2). MCM2 is a member of a family of six proteins (MCM 2-7), initially identified in Saccharomyces cerevisiae, but now known to be ubiquitous in eukaryotes. The six members of the family form a complex around chromosomal DNA at specific loci and mediate a number of functions including interactions with histone proteins in chromatin, and helicase activity – relaxing the tightly coiled DNA molecule and permitting the replication fork to progress. The activity of the MCM family of proteins is itself regulated by cell cycle dependent kinases. The MCM complex serves the role of licensing DNA replication, permitting it to occur once only during each cell cycle.
Role of MCM in cancer discovered by researchers at the University of Cambridge
Malignancy may be regarded as the breakdown of the regulated cell cycle, marked by increased and deregulated DNA replication and cell proliferation. It was anticipated that cells undergoing such deregulated DNA replication might demonstrate aberrant patterns of MCM expression, with MCM complex binding constitutively to nuclear DNA at times outwith those normally defined in the correctly regulated cell cycle. Work conducted at the University of Cambridge in the 1990s subsequently confirmed this hypothesis.
The discovery: MCM2 positive nuclei present in urine
Fully differentiated, quiescent cells would not be anticipated to demonstrate MCM2 positive nuclei. However, urine samples contain a diverse range of cell types, originating from both within the genitourinary tract and the immune system. Several of these populations would be anticipated to be engaged in the cell cycle. Skilled cytopathologists routinely use the morphological and staining characteristics to identify such cells. By not relying purely on a molecular approach, the additional parameters captured in collaboration with clinical cytopathologists from whole cells are currently being applied to eliminate such potential false positives from consideration in the assay.
Cytosystems' clinical technology headed for large-scale clinical trial
Using this patented technology, Cytosystems has undertaken ISO13485-accredited trials at five separate locations in the UK, utilising over 1,000 clinical samples to demonstrate the validity and utility of MCM-based bladder cancer determination. The company is now combining the sensitivity and specificity of monoclonal antibodies with the best aspects of current cytology and IT automation. With this fully-integrated assay system Cytosystems are proceeding to conduct large-scale clinical trials, as part of the development of our first MCM2-based product BladderLight™. Within this trial we will be testing some of our other clinical technology: a novel cell separation device, and digital analysis with proprietary diagnostic algorithms.