Analysis of an EGFR mutation by PNA clamping method in lung carcinoid tumors / 고신대학교의과대학학술지

BACKGROUND: Pulmonary carcinoid tumors consisting of typical carcinoid tumors (TC) and atypical carcinoid tumors (AC) are rare, accounting for 2-5% of all lung tumors. TC is considered a low-grade tumor with a rate of distant metastasis up to 12%. In contrast, ACs are more aggressive tumors, displaying a metastatic rate up to 70%. Surgery is the treatment of choice; however, the current treatment outcomes of metastatic lung carcinoids are discouraging. This study aimed to investigate the EGFR mutation using the PNA-mediated clamping method and to provide basic data for using EGFR-TK1 and its clinical implications. MATERIALS AND METHODS: A total of 14 cases that underwent surgery were diagnosed as carcinoid tumors and pathologically classified as TC and AC. The paraffin-embedded tissues were analyzed for EGFR mutations using the PNA-mediated PCR clamping technique. The mutant type was noted in the cases with a DeltaCt greater than 2.0. RESULT: Of 14 cases, eight were AC and six cases were TC. No known EGFR mutation was detected with a DeltaCt less than 2.0. CONCLUSION: The EGFR genotype determined using the PNA-mediated PCR clamping method was wild-type in all pulmonary carcinoid tumors. Therefore, the application of EGFR-TK1 is limited in pulmonary carcinoid tumors.

IDH Mutation Analysis in Ewing Sarcoma Family Tumors

BACKGROUND: Isocitrate dehydrogenase (IDH) catalyzes the oxidative decarboxylation of isocitrate to yield alpha-ketoglutarate (alpha-KG) with production of reduced nicotinamide adenine dinucleotide (NADH). Dysfunctional IDH leads to reduced production of alpha-KG and NADH and increased production of 2-hydroxyglutarate, an oncometabolite. This results in increased oxidative damage and stabilization of hypoxia-inducible factor alpha, causing cells to be prone to tumorigenesis. METHODS: This study investigated IDH mutations in 61 Ewing sarcoma family tumors (ESFTs), using a pentose nucleic acid clamping method and direct sequencing. RESULTS: We identified four cases of ESFTs harboring IDH mutations. The number of IDH1 and IDH2 mutations was equal and the subtype of IDH mutations was variable. Clinicopathologic analysis according to IDH mutation status did not reveal significant results. CONCLUSIONS: This study is the first to report IDH mutations in ESFTs. The results indicate that ESFTs can harbor IDH mutations in previously known hot-spot regions, although their incidence is rare. Further validation with a larger case-based study would establish more reliable and significant data on prevalence rate and the biological significance of IDH mutations in ESFTs.