Author of

• 16879

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  P1.07 - Poster Session with Presenters Present (ID 459)

  • Event: WCLC 2016
  • Type: Poster Presenters Present
  • Track: SCLC/Neuroendocrine Tumors
  • Presentations: 1
  • Moderators:
  • Coordinates: 12/05/2016, 14:30 - 15:45, Hall B (Poster Area)

  • 16918

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    P1.07-039 - Insulinoma-Associated 1 (INSM1) Immunohistochemical Expression in Lung Neuroendocrine Tumors (ID 5407)

    14:30 - 14:30  |  Author(s): K. Inamura
    • Abstract

    Background:
    Insulinoma-associated 1 (INSM1) is a transcription factor, and expressed during early embryonal development. In vitro and in vivo, INSM1 has been reported to regulate the neuroendocrine differentiation pathway represented by achaete-scute complex homolog-like1 (ASCL1) and neuroendocrine molecules (CGA, SYP, CD56) in lung cancer. We examined association between INSM1 protein expression and clinicopathological characteristics in lung neuroendocrine tumors.
    
    Methods:
    Using 139 consecutive surgically resected cases of lung neuroendocrine tumor (78 small cell lung carcinomas [SCLCs], 42 large cell neuroendocrine carcinomas [LCNECs], and 19 carcinoids), we evaluated INSM1 and ASCL1 immunohistochemical expression, and examined the association of INSM1 and ASCL1 expression with clinicopathological features.
    
    Results:
    For the 78 SCLCs, male/female ratio was 3.9:1, age ranged 46-84 with a median of 67 years, average cumulative smoking was 50.6 (pack-years), and 60/78 (77%) were positive for any one of neuroendocrine molecules. For the 42 LCNECs, male/female ratio was 5:1, age ranged 42-84 years with a median of 70, and average smoking was 47.9. For the 19 carcinoids, male/female ratio was 0.73:1, age ranged 38-85 years with a median of 67, and average smoking was 21.9. All of SCLCs positive for neuroendocrine molecules (n=60) were positive for INSM1 (60/60) and 72% positive for ASCL1 (43/60). In the SCLCs negative for all neuroendocrine molecules (n=18), 72% were positive for INSM1 (13/18) and all of them were negative for ASCL1 (0/18). For LCNECs, 57% were positive for INSM1 (24/42) and 50% were positive for ASCL1 (21/42). All of the carcinoids were positive for INSM1 (19/19) and 53% of them were positive for ASCL1 (10/19). Taken together, INSM1 and ASCL1 were detectable in lung neuroendocrine tumors by immunohistochemistry in 83% (116/139) and 53% (74/139), respectively.
    
    Conclusion:
    Our study suggests INSM1 is a sensitive and useful neuroendocrine marker, even for SCLC without apparent expression of neuroendocrine markers.