situ hibridizasyon yöntemi i - Çukurova Üniversitesi

ABSTRACT
Evaluation of DNA Copy Number Changes and Chromosomal Aberrations in
Melanocytic Tumors by Fluorescence In-situ Hybridization Method, Investigation
of Its Differential Diagnosis and Prognostic Value
Introduction-aim: Melanocytic tumors characterized by neoplastic proliferation
of melanocytes and have highly wide and heterogeneous spectrum morphologically and
genetically. Melanoma responsible for almost 60% of fatal skin tumors. Therefore,
molecular studies for etiopathogenesis increasingly gain importance. In our study, we
aimed to research the diagnostic value of four-colored fluorescent in situ hybridization
method targeted of 6p25, 6q23, 11q13 and centromeric region of chromosome sixth at
particularly melanocytic tumors which have diagnostic challenge. We aimed to
determine differences of chromosomal aberrations in melanocytic nevus, displastic
nevus, non-metastatic melanoma and metastatic melanoma and its place at biological
behavior of malignant melanoma, comparing conventional morphological and
prognostic criteria.
Material and Method: In this study, we involved 74 melanocytic lesions, which
diagnosed at Cukurova University School of Medicine Pathology Department. 17 cases
(23%) had benign feature, 28 cases (38%) had borderline feature, 29 cases (39%) had
malign feature. Borderline and malign lesions were selected from among the patients
who have clinical follow-up. Fluorescence in situ hybridization procedure was
performed on 3µm thickness sections of formaline fixed-paraffin embedded tissues
taken from these cases. The results were examined by fluorescence microscope and
numeric value of different four colors corresponding to copy numbers of genes were
recorded.
Results: Fluorescence in situ hybridization was negative in all of 17 melanocytic
nevi cases; positive in 6 of 19 cases of borderline lesions which have diagnostically
challenging; positive in 10 of 11 non-metastatic melanoma and positive in all of 18
metastatic melanoma cases. The evaluation of test results were based on
histopathological diagnosis as clearly benign and malignant lesions and were based on
the characteristics of lesions that determined according to clinical behavior for
borderline melanocytic lesion. Test sensitivity was 98,5% and specifity was 100%.
Quantitative values of signal parameters compared as pairs in benign, borderline, nonmetastatic
and metastatic groups. All parameters, except of 6q23 loss had statistically
significant difference when compared benign and borderline groups, borderline and
non-metastatic groups, but there was no statistically significant difference between nonmetastatic
and metastatic melanom. Abnormal 6p25 and loss of 6q23 had strong
correlations to prognosis, and 11q13 and 6q23 amplifications had weakly correlations to
prognosis. 6p25 positivity was observed frequently at acral region (83,3%) and lower
extremity (75%). Significant correlation were determined between 6p25 abnormality
and 11q13 amplification with tumor diameter (p=0,001, p=0,046 respectively). There
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