Nonlinear spectral imaging of human normal skin, basal cell carcinoma and squamous cell carcinoma based on two-photon excited fluorescence and second-harmonic generation

Advances and challenges in label-free nonlinear optical imaging using two-photon excitation fluorescence and second harmonic generation for cancer research

“…Provenzano et al [116] observed that high collagen density promoted tumorigenesis, invasion and metastasis in a transgenic mice breast cancer model. In stark contrast to the mentioned study, Xiong et al [117] found that collagen appeared broadened, integrated and well distributed in normal skin, while it was fragmented, reduced and disordered in squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) of human skin. Loss of collagen associated SHG was also observed in neoplasia of oropharynx, [118], lungs [119], rectum [75], oesophagus [120], while SHG was observed to be absent in breast carcinoma [70].…”

In vivo nonlinear spectral imaging as a tool to monitor early spectroscopic and metabolic changes in a murine cutaneous squamous cell carcinoma model

“…This in turn leads to reduced detection of SHG signal from skin surface due to signal attenuation. Another possible cause for diminished SHG signal with advancing stages of carcinogenesis could be dermal collagen degradation or lysis during epidermal invasion into dermis as observed by Xiong et al [26]. However this possibility seems improbable in the present study for the following reasons -a) advanced skin tumors such as SCC and carcinoma-in-situ had been excluded from the present data set and b) no dermal invasion was observed histopathologically in the corresponding H&E stained sections of the assessed skin with preclinical hyperplasia and clinically visible early skin tumors, which rules out epidermal invasion into dermis.…”

“…Studies that used nonlinear optical imaging for skin cancer have so far relied mainly on fluorescence lifetime measurements [22][23][24], instead of emission spectral characteristics. Among the few studies that did use NLSI for skin cancer diagnosis, the experiments had been performed on ex vivo human skin biopsies [25][26][27]. The only notable study that employed in vivo NLSI for cancer characterization was performed in the hamster oral cavity cancer model by Edward et al [28].…”

Application of multiphoton microscopy in dermatological studies: A mini-review

“…Excited state absorption has been shown to effectively image melanin, and this was developed into a portable imaging system for the diagnosis of melanoma by Teuchner et al . 82 Pump-probe optical coherence microscopy was used to image melanoma by Wan and Applegate, 83 , 85 and melanoma was also studied using two-photon photoacoustic microscopy by Oh et al ., 84 who exploited the fact that melanin has a high two-photon absorption cross section. CARS has been combined with SGH and two-photon fluorescence by Vogler et al .…”