Infrared Spectra of Basal Cell Carcinomas are Distinct from Non-Tumor-Bearing Skin Components

Abstract

Infrared spectroscopy, by probing the molecular vibration of chemical bonds, directly indicates tissue biochemistry. An expanding body of literature suggests that infrared spectra distinguish diseased from normal tissue. The authors used infrared spectroscopy to examine basal cell carcinoma to explore distinctive characteristics of basal cell carcinoma versus normal skin samples and other skin neoplasms. Spectra of epidermis, tumor, follicle sheath, and dermis were acquired from unstained frozen sections, and analyzed qualitatively, by t-tests and by linear discriminant analyses. Dermal spectra were significantly different from the other skin components mainly due to absorptions from collagen in dermis. Spectra of normal epidermis and basal cell carcinoma were significantly different by virtue of subtle differences in protein structure and nucleic acid content. Linear discriminant analysis characterized spectra as arising from basal cell carcinoma, epidermis, or follicle sheath with 98.7% accuracy. Use of linear discriminant analysis accurately classified spectra as arising from epidermis overlying basal cell carcinoma versus epidermis overlying nontumor-bearing skin in 98.0% of cases. Spectra of basal cell carcinoma, squamous cell carcinoma, nevi, and malignant melanoma were qualitatively similar. Distinction of basal cell carcinoma, squamous cell carcinoma, and melanocytic lesions by linear discriminant analyses, however, was 93.5% accurate. Therefore, spectral separation of abnormal versus normal tissue was achieved with high sensitivity and specificity, which points to infrared spectroscopy as a potentially useful screening tool for cutaneous neoplasia.

Basal cell carcinoma: biology, morphology and clinical implications

“…[79][80][81] By noninvasive methods, in-vivo NIR spectroscopy can be used to map the extent of BCCs and also to distinguish them from other cutaneous tumors with a high degree of accuracy. [79][80][81][82][83] That the two proposed mechanisms of tumorigenesis are complementary is suggested by the fact that shh-expressing cells also manifest increased expression of bcl-2, 84 likely through activation of the Gli proteins that are expressed in the outer root sheath of the normal hair follicle and in BCCs; 65 Gli-2 in particular appears to play an important role in the activation of the BCL2 gene. 70 …”

Diagnosis of tumors during tissue-conserving surgery with integrated autofluorescence and Raman scattering microscopy

“…Recently, quantitative diagnosis based solely on the spectral information of tissue with simultaneous sensitivity and specificity higher than 90% was demonstrated for many cancer types, including skin (11)(12)(13)(14)(15), esophagus (16), prostate (17)(18)(19)(20)(21), breast (22), and lung (23, 24) (here, sensitivity represents the percentage of correctly detected tumor samples relative to the total number of tumor samples, and specificity is the percentage of correctly identified nontumor samples relative to the total number of nontumor samples). Nevertheless, achieving objective diagnosis while maintaining a high spatial resolution (20-50 μm) required tissue sectioning and long data acquisition times: typically 30-40 min/mm 2 for infrared microscopy and 5-20 h/mm 2 for Raman microscopy (13,15,20,23,25).…”

Methods and biomarkers for the diagnosis and prognosis of cancer and other diseases: Towards personalized medicine

“…A similar study using Fourier-transformed infrared (FT-IR) spectroscopy of mdx muscles was able to follow the progression of fibrosis (collagen content and accumulation) during dystrophy, and also traced the partial alleviation of collagen accumulation after treatment with steroids (Shaw et al, 1996). These studies from the muscle literature, illustrate how a correlation of measures taken independently from different approaches can extend the impact of the conclusions that are reached, and similar combination studies of cancer diagnostics, screening, prognostic and treatment outcome have been shown highly advantageous (McIntosh et al, 1999;Kirkham et al, in press;Shah et al, 2006;Delorme and Weber, 2006;Weber et al, 2006;Huzjan et al, 2005).…”