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Jianzhu Zhao



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    P1 - Poster Viewing (ID 5)

    • Event: NACLC 2019
    • Type: Poster Session
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 10/11/2019, 16:45 - 18:00, Exhibit Hall
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      P1.17 - Comparison of Genetic Profiles of Pulmonary Sarcomatoid Carcinoma (PSC) Between Asian and Western Populations (ID 36)

      16:45 - 18:00  |  Author(s): Jianzhu Zhao

      • Abstract

      Background:
      Pulmonary sarcomatoid carcinoma (PSC) is a rare type of NSCLC characterized by aggressive behavior and poor clinical outcome. Earlier reports have revealed the genomic characterization of PSC in Western populations. However, the genomic alterations of Chinese PSC remain unclear.


      Method:
      A total of 21 Chinese PSC patients were enrolled in the study. 14 Tissue biopsy and 10 ctDNA testing were analyzed for mutation profiling. All samples were analyzed using next-generation sequencing based target region capture method, which enables simultaneously assess genomic profile across at 1021 cancer genes. Tumor mutational burden (TMB) was calculated from 1.17 megabases (Mb) of sequenced DNA. Western PSC genomic data were quoted from Schrock’s study.


      Results:
      A total of 24 samples from 21 PSCs were enrolled in this study. The most frequently altered genes were TP53 (58.3%), EGFR (29.2%), KRAS (29.2%), SMARCA4 (20.8%), MET (16.7%), MLL3 (16.7%), NF1 (16.7%), EPHA5 (12.5%), GATA3(12.5%), and ATM (12.5%) in our patient group. In comparison with Schrock’s study, alterations in TP53, KRAS, MET and NF1 were appeared in both races with high frequencies, some gene alterations such as SMARCA4, MLL3, ATM, EPHA5 and GATA3 were more commonly occurred in Asian patients, and other genes including CDKN2A, CDKN2B, TERT, PTEN, LRP1B and PIK3CA were more commonly existed in Western patients. And 70.8% PSC featured a genomic alteration in KRAS (29.2%) or one of seven genes recommended for testing in NSCLC NCCN guidelines, including EGFR (29.2%), MET (16.7%), ALK (8.3%). The frequency of EGFR mutation was higher in Asian patients than in Western patients. ALK alterations was only identified in our group, whereas BRAF, HER2 or RET alterations were only identified in Western populations. We also found that EGFR alterations were significantly more common in TP53 mutated cases than in TP53 wild-type cases (42.9% versus 10.0%). In addition, high TMB (>9 mutations per Mb) was found in 29.2% of cases, which was higher than that in 20% of the Western populations.


      Conclusion:
      Genetic profiles differences were observed between Asian and Western PCS patients that maybe lead to different disease characteristics. Limited by a small number of samples, our study is still ongoing for validation these findings.