Comparative Analysis of EGFR Immunohistochemical Expression and Mutational Analysis in Metastatic Basal Cell Carcinomas.
William R Porter, John D Schwartz, Mitual B Amin, LeeAnn Thal, Dmitry Kazakov, Michal Michal, Shakil Merchant, Rajwant K Malhotra. William Beaumont Hospital, Royal Oak, MI; University Hospital Plzen, Pilsen, Czech Republic; Methodist Hospital, San Antonio, TX
Background: Basal cell carcinoma is a common and indolent tumor that rarely metastasizes (incidence: 0.0028 to 0.5%). The median survival of metastatic basal cell carcinoma (MBCC) is 10-14 months and the 5-year survival is approximately 10%. One of our prior studies examined EGFR immunohistochemical expression in MBCC, which showed positive expression in all examined cases. A literature search did not reveal any studies on EGFR mutation analysis in MBCC. Given the poor prognosis and desire of oncologists to try newer targeted therapy as a last resort, such as Imatinib, examination for EGFR mutations in these aggressive tumors could be potentially fruitful.
Design: Seven samples were selected of metastatic disease to the following: kidney(1), lung(2), lymph node(2), soft tissue(1), and vetebra (1). The vetebral metastasis was excluded from mutation analysis due to decalcificied nature of specimen. Tumors were stained for EGFR (DakoCytomation pharmDx kit) as directed. RNA was extracted from corresponding paraffin blocks using the RNAeasy FFPE kit, and DNA was extracted using the QIAamp DNA mini kit. In-house real time PCR was used to identify variant III EGFR. The QIAGEN EGFR PCR kit was used to identify 28 of the most common mutations of the EGFR gene.
Results: There was positive EGFR immunohistochemical expression in all seven cases. No EGFR mutations were detected in the 4 samples that could be analyzed (wild type). Mutation analysis for EGFR variant III showed similar absence of the mutation in 4 samples. Three cases had insufficient tissue for complete mutational analysis.
|Sample||Metastatic Site||EGFR IHC||EGFR vIII mutation||EGFR Mutation|