{
  "abstract": "The NKX2-1 gene, located on chromosome 14, encodes thyroid transcription factor 1 (TTF1), essential for lung development and expressed in peripheral lung cells.1 TTF1 is found in approximately 75% of adenocarcinomas of pulmonary origin. TTF1 immunohistochemistry (IHC) staining is a key marker to determine tumour origin, especially in lung lesions.2 Typically, positive TTF1 IHC suggests a pulmonary origin, while negative results suggest an extrapulmonary origin. However, this diagnostic approach may be confounded by genetic alterations, such as NKX2-1 mutations, which can reduce or eliminate TTF1 expression even in pulmonary tumours. This study examines the frequency of NKX2-1 mutations in solid tumours and discusses the implications for interpreting negative TTF1 IHC results, particularly in non-mucinous pulmonary carcinomas. Despite their rarity, NKX2-1 mutations can significantly impact the accuracy of TTF1-based diagnostic algorithms, underscoring the need for careful interpretation in surgical pathology.",
  "authors": [
    {
      "affiliations": [
        "Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA",
        "Laboratory Medicine, Unity Health Toronto, Toronto, Ontario, Canada"
      ],
      "name": "Ju-Yoon Yoon"
    },
    {
      "affiliations": [
        "Center for Personalized Diagnostics, University of Pennsylvania, Philadelphia, Pennsylvania, USA"
      ],
      "name": "Farah El-Sharkawy Navarro"
    },
    {
      "affiliations": [
        "Laboratory Medicine, Unity Health Toronto, Toronto, Ontario, Canada"
      ],
      "name": "Qiang Ding"
    },
    {
      "affiliations": [
        "Regional Genetics Laboratory, Kaiser Permanente, Oakland, California, USA"
      ],
      "name": "Jason Rosenbaum"
    },
    {
      "affiliations": [
        "Center for Personalized Diagnostics, University of Pennsylvania, Philadelphia, Pennsylvania, USA"
      ],
      "name": "Salvatore Priore"
    }
  ],
  "title": "NKX2-1 gene variants in solid tumours: the spectrum of gene variants and potential impact in surgical pathology diagnosis",
  "uid": "4e48deee-c301-515f-b1aa-28fe61369990"
}