In vivo pump-probe microscopy of melanoma: Characterizing shifts in excited state photodynamics with respect to invasiveness
Pump-probe microscopy is a multiphoton technique that generates molecular contrast from absorptive pigments, such as melanin. It holds the potential to be used as a non-invasive screening tool to discern whether a given early-stage melanoma has acquired the capacity for metastasis. Here, we examined lesions in a Braf(V600E)-driven model of melanoma to assess whether loss of the tumor suppressor gene Pten in a is accompanied by a shift in pigment expression, as measured in vivo by pump-probe microscopy. The data were analyzed to determine differences in the excited-state lifetime of melanins expressed in Pten-competent and Pten-loss pigmented lesions. Loss of the tumor suppressor Pten was found to be accompanied by a statistically significant decrease in pixel-average excited state lifetime (p = 1.3e-4).