Lack of evidence for prognostic value of epidermal growth factor receptor intron‐1 CA repeats for oral carcinomas

Abstract

Epidermal growth factor receptor (EGFR) expression is altered in several malignancies, including oral squamous cell carcinoma. A CA-repeat polymorphism in intron-1 (CA-SSR-1) of the EGFR gene is reported to influence EGFR expression and is associated with features of various solid tumors and outcomes of cancer patients. In the present study we evaluated the influence of length and zygosity of CA-SSR-1 on the survival of patients with oral squamous cell carcinoma. The length and zygosity of CA-SSR-1 was obtained through microsatellite analysis in 91 patients with oral cancer, who were treated in the Department of Oral and Maxillofacial Surgery of the University Medical Centre Hamburg Eppendorf, Germany, during the years 1998-2008. Follow up was conducted until 2016. Outcome measures were age, gender, tumor stage, occurrence of metastases, and date of recurrence or death. Statistical analysis was conducted using the chi-square test and the log-rank test. Neither length nor zygosity of the CA-SSR-1 in patients with oral squamous cell carcinoma was significantly correlated with sex, age, tumor size, tumor localization, lymph node involvement, metastasis status, disease-free survival, or overall survival. Length and zygosity of the CA-SSR-1 polymorphism in EGFR is not able to serve as a prognostic biomarker in White European patients with oral squamous cell carcinoma.

Epidermal growth factor receptor intron-1 CA repeat polymorphism on protein expression and clinical outcome in Taiwanese oral squamous cell carcinoma

“…The procedure for analysis of the EGFR intron 1 CA repeats length polymorphism was modified from previous reports 11, 19, 20 . Briefly, fluorescein-labeled forward primer 5′-FAM-GTTTGAAGAATTTGAGCCAACC-3′ and reverse primer 5′-GTCTGCACACTTGGCACACT-3′ was used for the PCR reaction, which began with initial heating for 12 min at 95 °C, followed by 30 cycles of denaturation at 94 °C for 30 s, annealing at 60 °C for 60 s, and extension at 72 °C for 60 s. The fragment length of the amplified PCR products based on the 500 LIZ size standards was determined using the ABI Prism 3100 DNA Analyzer with GeneScan software (Applied Biosystems, Foster City, CA).…”

“…We have previously shown that EGFR genetic mutations play a very minor role in OSCCs, whereas gene copy number was found to be significantly correlated with EGFR protein overexpression 4 . However, the role of the patient’s EGFR intron 1 CA repeat genotype in OSCC is rarely explored 11 . Since the EGFR intron 1 CA repeat genotype is known to be associated with the gene’s transcriptional activity, the CA repeat genotype has been implicated in cancer risk and in patient clinical outcome 12 .…”