Autofluorescence of breast tissues: evaluation of discriminating algorithms for diagnosis of normal, benign, and malignant conditions

Preclinical ex vivo evaluation of the diagnostic performance of a new device for in situ label-free fluorescence spectral analysis of breast masses

OBJECTIVES

To assess the diagnostic performance of a new device for in situ label-free fluorescence spectral analysis of breast masses in freshly removed surgical specimens, in preparation for its clinical development.

METHODS

Sixty-four breast masses from consenting patients who had undergone either a lumpectomy or a mastectomy were included. Label-free fluorescence spectral acquisitions were obtained with a 25G fibre-containing needle inserted into the mass. Data from benign and malignant masses were compared to establish the most discriminating thresholds and measurement algorithms. Accuracy was verified using the bootstrap method.

RESULTS

The final histological examination revealed 44 invasive carcinomas and 20 benign lesions. The maximum intensity of fluorescence signal was discriminant between benign and malignant masses (p < .0001) whatever their sizes. Statistical analysis indicated that choosing five random measurements per mass was the best compromise to obtain high sensitivity and high negative predictive value with the fewest measurements. Thus, malignant tumours were identified with a mean sensitivity, specificity, negative and positive predictive value of 98.8%, 85.4%, 97.2% and 93.5%, respectively.

CONCLUSION

This new in situ tissue autofluorescence evaluation device allows accurate discrimination between benign and malignant breast masses and deserves clinical development.

KEY POINTS

• A new device allows in situ label-free fluorescence analysis of ex vivo breast masses • Maximum fluorescence intensity discriminates benign from malignant masses (p < .0001) • Five random measurements allow a high negative predictive value (97.2%).

Optical redox imaging indices discriminate human breast cancer from normal tissues

Our long-term goal was to investigate the potential of incorporating redox imaging technique as a breast cancer (BC) diagnosis component to increase the positive predictive value of suspicious imaging finding and to reduce unnecessary biopsies and overdiagnosis. We previously found that precancer and cancer tissues in animal models displayed abnormal mitochondrial redox state. We also revealed abnormal mitochondrial redox state in cancerous specimens from three BC patients. Here, we extend our study to include biopsies of 16 patients. Tissue aliquots were collected from both apparently normal and cancerous tissues from the affected cancer-bearing breasts shortly after surgical resection. All specimens were snap-frozen and scanned with the Chance redox scanner, i.e., the three-dimensional cryogenic NADH/Fp (reduced nicotinamide adenine dinucleotide/oxidized flavoproteins) fluorescence imager. We found both Fp and NADH in the cancerous tissues roughly tripled that in the normal tissues ( p < 0.05 ). The redox ratio Fp/(NADH + Fp) was ? 27 % higher in the cancerous tissues ( p < 0.05 ). Additionally, Fp, or NADH, or the redox ratio alone could predict cancer with reasonable sensitivity and specificity. Our findings suggest that the optical redox imaging technique can provide parameters independent of clinical factors for discriminating cancer from noncancer breast tissues in human patients.

Detecting cervical cancer progression through extracted intrinsic fluorescence and principal component analysis

Intrinsic fluorescence spectra of the human normal, cervical intraepithelial neoplasia 1 (CIN1), CIN2, and cervical cancer tissue have been extracted by effectively combining the measured polarized fluorescence and polarized elastic scattering spectra. The efficacy of principal component analysis (PCA) to disentangle the collective behavior from smaller correlated clusters in a dimensionally reduced space in conjunction with the intrinsic fluorescence is examined. This combination unambiguously reveals the biochemical changes occurring with the progression of the disease. The differing activities of the dominant fluorophores, collagen, nicotinamide adenine dinucleotide, flavins, and porphyrin of different grades of precancers are clearly identified through a careful examination of the sectorial behavior of the dominant eigenvectors of PCA. To further classify the different grades, the Mahalanobis distance has been calculated using the scores of selected principal components.

Optical spectroscopy: current advances and future applications in cancer diagnostics and therapy

Optical spectroscopy (OS) is a tissue-sensing technique that could enhance cancer diagnosis and treatment in the near future. With OS, tissue is illuminated with a selected light spectrum. Different tissue types can be distinguished from each other based on specific changes in the reflected light spectrum that are a result of differences on a molecular level between compared tissues. Therefore, OS has the potential to become an important optical tool for cancer diagnosis and treatment monitoring. In recent years, significant progress has been made in the discriminating abilities of OS techniques between normal and cancer tissues of multiple human tissue types. This article provides an overview of the advances made with diffuse reflectance, fluorescence and Raman spectroscopy techniques in the field of clinical oncology, and focuses on the different clinical applications that OS could enhance.

Autofluorescence of osteoporotic mouse femur bones: a pilot study

OBJECTIVE

The objective of this study was to evaluate the efficacy of laser-induced fluorescence (LIF) in combination with principal component analysis (PCA) to characterize osteoporotic conditions induced by ovariectomy (OVX) in mice.

BACKGROUND DATA

The dual energy X-ray absorptiometry is the gold standard methodology routinely used to diagnose osteoporosis. In recent years, the use of LIF to characterize human disease and to aid in diagnosis has shown great promise. However, this technique has not been much exploited for monitoring osteoporosis.

MATERIALS AND METHODS

Swiss albino mice were sacrificed 2, 3, 4, and 5 wk after OVX and their femur bones were excised. The same protocol was used for age-matched female controls (no OVX). The LIF spectra from different regions of the bones were recorded and compared using PCA.

RESULTS

A significant change in the fluorescence pattern of osteoporotic bones compared with the control was indicated by PCA match/no-match analysis. A region-wise PCA match/no-match analysis of the spectral changes against respective region calibration sets indicated more no-matches in the fifth week bones compared with the others. Further, the spectral differences were more prominent in the proximal and distal parts of the bones. In addition to the PCA, Gaussian curve fitting was also performed on control, third week, and fifth week bone spectra to identify different spectral components in them.

CONCLUSION

This preliminary study using fluorescence spectroscopy in combination with PCA clearly demonstrated osteoporotic changes in mouse femur bones at different time points after OVX, suggesting possible human applications.