Molecular diagnosis of basal cell carcinoma and other basaloid cell neoplasms of the skin by the quantification of Gli1 transcript levels.
BACKGROUND
Distinguishing basal cell carcinoma (BCC) from other benign and malignant skin tumors is sometimes a difficult task for the pathologists. Because the activation of hedgehog signals and the up-regulation of its critical transcriptional factor Gli1 are well documented in BCC, a molecular technique measuring Gli1 transcripts may aide the diagnosis.


METHODS
Gli1 transcript levels were measured by real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR) using RNA extracted from formalin-fixed, paraffin-embedded tissues of 68 cases of various skin tumors. Hematoxylin and eosin-stained pathology slides were independently reviewed by three expert dermatopathologists.


RESULTS
The histological diagnoses were unambiguous in 53 tumors. The tumors included BCC (21), squamous cell carcinoma (13), seborrheic keratoses (8), trichoepithelioma (5), eccrine poroma/porocarcinoma (4), and sebaceous epithelioma/carcinoma (2). In these unambiguous cases, all BCC and trichoepithelioma tumors showed high expression of Gli1mRNA, while the expression was virtually absent in other tumors. The diagnosis was discordant among three pathologists in the remaining 15 tumors. Histological diagnoses included BCC, BCC with sebaceous differentiation, sebaceoma/sebaceous epithelioma, trichoblastoma, trichoepithelioma, basaloid follicular harmartoma, basosquamous carcinoma, etc. Six of them showed high Gli1 transcript levels.


CONCLUSIONS
Quantification of Gli1 transcripts by RT-PCR is helpful in discriminating BCC and trichoepithelioma from other skin tumors.
Hatta
Naohito
N
Department of Dermatology, Postgraduate School of Medicine, Kanazawa University, Kanazawa, Japan.
Hirano
Takashi
T
Kimura
Tetsunori
T
Hashimoto
Ken
K
Mehregan
Darius R
DR
Ansai
Shinichi
S
Takehara
Kazuhiko
K
Takata
Minoru
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D002280:Basal Cell Carcinoma / Q000175:diagnosis* / Q000235:genetics; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000235:genetics; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D000071676:Zinc Finger Protein GLI1
D014408:Biomarkers, Tumor; D015513:Oncogene Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; D014157:Transcription Factors; D000071676:Zinc Finger Protein GLI1