Despite advances in treatment, death from aggressive squamous cell carcinoma (SCC) is increasing; with mortality overtaking melanoma worldwide. For at risk patients, the aged, immunosuppressed, and those with rare genetic diseases, such as recessive dystrophic epidermolysis bullosa (RDEB) the problem is exacerbated because of rapid spread, lack of effective treatments, lack of biomarkers, and lack of a minimally invasive diagnostic that would allow for convenient tracking of clinical course and response to treatment. In the case of RDEB patients, treatment of malignant disease often means amputation of an affected limb. These patients also have chronic wound healing defects and cannot tolerate frequent excision biopsies. In collaboration with EB House Austria, we have identified miR-10b as a marker of aggressive SCCs and begun development of a minimally invasive liquid biopsy protocol for point-of-care diagnostics, which can be applied to RDEB patients as well as the broader group of at-risk patents.
In this study, a unique ISH protocol has been used to characterise miR-10b expression in SCCs in cell lines, and to identify circulating cells in the blood of malignant SCC patients, using size-filtration (ScreenCell®), and common epithelial (pan-cytokeratin) and blood cell markers (CD45).
Through precise targeting of miR-10b in samples, we have found a relatively higher expression of miR-10b in more malignant patient derived cell lines, when compared to control healthy keratinocytes. This study has also validated the possibility of multiplexing miR-10b with an internal negative scrambled probe within the same sample to reduce cell-to-cell variation. Putative SCCs have been identified from spike-in blood samples and patient samples.
Overall, this study has demonstrated that miR-10b marks aggressive SCCs from RDEB and non RDEB patients and shown that it can be applied to the liquid biopsy.