Allele-specific PCR method for identification of EGFR mutations in non-small cell lung cancer: formalin-fixed paraffin-embedded tissue versus fresh tissue

Vol. 57 No. 2 Suppl., 2016
This supplement was not sponsored by Outside Organizations.

ROMANIAN JOURNAL of MORPHOLOGY and EMBRYOLOGY

Bogdan Andrei Suciu, Zsuzsanna Pap, Lorand Denes, Klara Brinzaniuc, Constantin Copotoiu, Zoltan Pavai

The study of epidermal growth factor receptor (EGFR) gene mutations in lung adenocarcinoma patients has a special clinical significance in the selection of patients for tyrosine-kinase inhibitor therapy. The aim of this study was to identify patients with EGFR mutations using allele-specific polymerase chain reaction (PCR), from formalin-fixed paraffin-embedded (FFPE) tissue and fresh tissue (FT). Materials and Methods: We performed a retrospective study using 13 cases of FFPE lung adenocarcinoma, and a prospective study using seven fresh samples of lung carcinomas (FT), collected by intraoperative dissection of the tumors. Using the DNA extracted from the FFPE tissue and FT, we attempted to identify deletions of exon 19 and point mutations of exon 21, according to the allele-specific PCR method described by Dahse et al. (2008). Results: In all seven cases of FT (three adenocarcinomas, three squamous carcinomas, one large-cell carcinoma), we identified the wild type allele and the internal control in case of exon 19, and the wild type allele for exon 21, but not the mutated alleles. Considering that no standard method for formalin fixation and paraffin embedding has been implemented at the Laboratory of Pathology, the DNA extracted from these samples became fragmented and damaged, which compromised the results of PCR testing aimed at the detection of EGFR mutations. Conclusions: The presented method can be implemented at our laboratory to identify these mutations from fresh tissue collected during surgical resection. Additionally, standardization of formalin fixation and paraffin embedding of surgical samples is required, in order the enable subsequent processing using molecular biology methods.

Corresponding author: Zsuzsanna Pap, Associate Professor, MD, PhD; e-mail: papzsuzsa@yahoo.com

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ROMANIAN JOURNAL of MORPHOLOGY and EMBRYOLOGY

Roxana Maria Pascu, Claudiu Margaritescu, Monica Mihaela Craitoiu, Alma Maria Florescu, Ileana Cristiana Croitoru, Adelina Gabriela Bobic, Ciprian Laurentiu Patru, Gheorghe Dan Malaescu, Stefania Craitoiu

Pseudoepitheliomatous hyperplasia is a benign reactivated epithelial lesion secondary to another pathology, whose incidence is difficult to establish. There still exist controversies regarding the origin and pathogenesis of these lesions. For this purpose, we performed an immunohistochemical study upon 20 cases of oral pseudoepitheliomatous hyperplasia associated with inflammatory and neoplastic conditions, investigating a series of markers with a possible pathogenic potential in developing this type of lesions. Thus, the immunoreactivity study for beta-catenin showed the presence of a membrane reactivity in all the stratum spinosum and a predominantly cytoplasmatic reactivity, more rarely a nuclear one, in the cells of the basal stratum cells, especially in the epithelial apices that descend deeply in the chorion. Instead, in the case of vimentin, the reactivity was present only in the epithelial apices, especially in the peripheral cells, in comparison to the central ones, and especially in the cases where the epithelial apices descended deeply in the sublesional chorion. Moreover, we observed that the MMP9 reactivity in pseudoepitheliomatous hyperplasia lesions was present in the cells at the epithelium-chorion interface and especially in the epithelial apices that descend deeply into the chorion, and also in the epithelial chorion and networks. The study for CXCR4 immunoreactivity showed a good reactivity in almost all layers of this hyperplastic lesion, with a maximum reactivity especially inside the epithelial apices that descend deeply in the sublesional chorion. Such an immunoprofile suggests the ability of the oral epithelial cells to undergo an epithelial mesenchymal transition process, thus acquiring mesenchymal characteristics through which it deeply migrates in the subadjacent chorion and contributes to the formation of epithelial apices in pseudoepitheliomatous hyperplasia. Moreover, the invasive ability of these lesions is also given by the average quantity of matrix metalloproteinases present in the epithelium-chorion interface determined by the activation of CXCR4 receptors at this level.

Corresponding author: Claudiu Margaritescu, Professor, MD, PhD; e-mail: c_margaritescu2000@yahoo.com

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