Pedro De Marchi
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Gustavo Noriz Berardinelli
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Rodrigo de Oliveira Cavagna
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Icaro Alves Pinto
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Flavio Augusto Ferreira da Silva
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Background: Microsatellite instability (MSI) in non-small cell lung cancer (NSCLC) is uncommon; however, most studies refer to European and Asian populations. There are currently no data on MSI frequency in highly admixed populations, such as the one represented by Brazilian NSCLC patients. Aim: This study aimed to evaluate the frequency of MSI in Brazilian NSCLC patients. Methods: We evaluated 526 patients diagnosed with NSCLC at the Barretos Cancer Hospital (Brazil). The molecular MSI evaluation was performed using a hexa-plex marker panel by polymerase chain reaction followed by fragment analysis. The mutation profile of MSI-positive cases was performed using next-generation sequencing. Results: Only 1 patient was MSI positive (0.19%). This patient was a female, white, and active smoker, and she was diagnosed with clinical stage IV lung adenocarcinoma at 75 years old. The molecular profile exhibited 4 Tumor Protein p53 (TP53) mutations and the absence of actionable mutations in the Epidermal Growth Factor Receptor (EGFR), Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS), or V-Raf Murine Sarcoma Viral Oncogene Homolog B1 (BRAF) genes. Conclusions: The frequency of MSI in Brazilian NSCLC patients is equally rare, a finding that is consistent with the current literature based on other populations such as Europeans, North Americans, and Asians.
Commentary: The prognostic value of Kirsten rat sarcoma viral oncogene mutation for non–small cell lung cancer: One size does not always fit all