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J Cancer 2017; 8(1):146-151. doi:10.7150/jca.16108

Research Paper

Low Incidence along with Low mRNA Levels of EGFR^vIII in Prostate and Colorectal Cancers Compared to Glioblastoma

Joanna Peciak^1,2✉, Wojciech J Stec¹, Cezary Treda^1,2, Magdalena Ksiazkiewicz¹, Karolina Janik^1,2, Marta Popeda¹, Maciej Smolarz¹, Kamila Rosiak^1,2, Krystyna Hulas-Bigoszewska¹, Waldemar Och³, Piotr Rieske^1,2, Ewelina Stoczynska-Fidelus^1,2

1. Department of Research and Development, Celther Polska, Ltd., Milionowa 23, 93-193 Lodz, Poland;
2. Department of Tumor Biology, Medical University of Lodz, Zeligowskiego 7/9, 90-752 Lodz, Poland;
3. Clinical Department of Neurosurgery, The Voivodal Specialistic Hospital in Olsztyn, Zolnierska 18, 10-561 Olsztyn, Poland.

Abstract

Background: The presence as well as the potential role of EGFR^vIII in tumors other than glioblastoma still remains a controversial subject with many contradictory data published. Previous analyses, however, did not consider the level of EGFR^vIII mRNA expression in different tumor types. Methods: Appropriately designed protocol for Real-time quantitative reverse-transcription PCR (Real-time qRT-PCR) was applied to analyze EGFR^vIII and EGFR^WT mRNA expression in 155 tumor specimens. Additionally, Western Blot (WB) analysis was performed for selected samples. Stable cell lines showing EGFR^vIII expression (CAS-1 and DK-MG) were analyzed by means of WB, immunocytochemistry (ICC) and fluorescence in situ hybridization (FISH). Results: Our analyses revealed EGFR^vIII expression in 27.59% of glioblastomas (8/29), 8.11% of colorectal cancers (3/37), 6.52% of prostate cancers (3/46) and none of breast cancers (0/43). Despite the average relative expression of EGFR^vIII varying greatly among tumors of different tissues (approximately 800-fold) or even within the same tissue group (up to 8000-fold for GB), even the marginal expression of EGFR^vIII mRNA can be detrimental to cancer progression, as determined by the analysis of stable cell lines endogenously expressing the oncogene.

Conclusion: EGFR^vIII plays an unquestionable role in glioblastomas with high expression of this oncogene. Our data suggests that EGFR^vIII importance should not be underestimated even in tumors with relatively low expression of this oncogene.

Keywords: EGFR^vIII, prostate cancer, colorectal cancer, breast cancer, glioblastoma, Real-time quantitative reverse-transcription PCR.