Capture and Isolation of Circulating Melanoma Cells Using Photoacoustic Flowmetry.

Early detection of cancer has been a goal of cancer research in general and melanoma research in particular (Birnbaum et al., Lancet Glob Health 6:e885-e893, 2018; Alendar et al., Bosnian J Basic Med Sci 9:77-80, 2009). Early detection of metastasis has been targeted as pivotal to increasing survival rates (Menezes et al., Adv Cancer Res 132:1-44, 2016). Melanoma, though curable in its early stages, has a dramatic decrease in survival rates once metastasis has occurred (Sharma et al., Biotechnol Adv 36:1063-1078, 2018). The transition to metastasis is not well understood and is an area of increasing interest. Metastasis is always premeditated by the shedding of circulating tumor cells (CTCs) from the primary tumor. The ability to isolate rare CTCs from the bloodstream has led to a host of new targets and therapies for cancer (Micalizzi et al., Genes Dev 31:1827-1840, 2017). Detection of CTCs also allows for disease progression to be tracked in real time while eliminating the need to wait for additional tumors to grow. Using a photoacoustic flowmeter, in which we induce ultrasonic responses from circulating melanoma cells (CMCs), we identify and quantify these cells in order to track disease progression. Additionally, these CMCs are captured and isolated allowing for future analysis such as RNA-Seq or microarray analysis.