Medizinische Universität Graz - Research portal
Selected Publication:
Mayer, G.
Two Independent Standardised Approaches to Quantify Chronic Sun Exposure in Human Skin Samples of Malignant Melanoma: Histological Staining of Solar Elastosis and Analysis of Loss of Autofluorescence in Elastic Fibres
Humanmedizin; [ Diplomarbeit ] ; 2015. pp.
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- Authors Med Uni Graz:
- Advisor:
- Aberer Werner
- Wolf Peter
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- Abstract:
- Sunlight as potentially hazardous radiation and a risk factor for the development of dermatological conditions such as non-melanoma skin cancer is well documented. The exact correlation between ultraviolet radiation and the pathogenesis of malignant melanoma, on the other hand, is still somewhat obscure, more complex and certainly does not follow a linear model. The degree of the impact of accumulated solar irradiation onto skin is generally histologically assessed by experienced pathologists who usually subjectively assign the amount of solar elastosis in H&E stained skin samples to semiquantitative classes. A standardised quantitative approach to determine the degree of extrinsic skin aging in human specimens could be useful for epidemiological studies. In this diploma thesis, two independent approaches to quantify the degree of extrinsic skin aging were established and tested in 49 samples of human cutaneous malignant melanoma from Australia: 1) A colour-based computer program quantified the amount of elastic fibres and elastotic bulk in specimens stained with Unna’s Orcein Technique and Light Green (Positivity-Method, PM). 2) The loss of autofluorescent activity in superficial H&E stained elastic fibres at an excitation wavelength of 490nm was quantified (Loss of Fluorescence-Method, LoFM). For both methods, threshold values were determined and tested for their accuracy in separating the specimens into three semiquantitative groups of chronic sun damage (CSD; “mild”, “moderate” and “marked”) which they were previously assigned to by microscopic examination at the hands of three collaborating Australian pathologists. Threshold values between classes mild and moderate CSD and between moderate and marked CSD were tested: For the PM and the LoFM, Youden’s indexes of these threshold values were calculated at 0.727 (mild-moderate) and 0.869 (moderate-marked) and at 0.786 (mild-moderate) and 0.793 (moderate-marked), respectively. Furthermore, a Pearson product-moment correlation coefficient between the two methods was determined at 0.899. The obtained statistical results indicate that both methods established in this thesis can be used to objectively quantify the degree of extrinsic skin aging in human skin. Hence, they represent reliable alternatives to the subjective and semiquantitative approach currently used in most of the medical research projects.