Author of

• 11866

  +

  P2.18 - Poster Session 2 - Pathology (ID 176)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Pathology
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/29/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 11873

    +

    P2.18-007 - Correlating Histologic and Molecular Features in the Lung Adenocarcinoma TCGA Project (ID 1698)

    09:30 - 09:30  |  Author(s): J. Suh
    • Abstract

    Background
    Our understanding of the molecular landscape of lung adenocarcinoma (ADC) is evolving rapidly. Furthermore, the IASLC/ATS/ERS lung ADC classification was recently published. The histologic and molecular correlations have not yet been thoroughly explored in this rapidly changing field. We sought to investigate the molecular findings according to the IASLC/ATS/ERS classification. .

    Methods
    Aperio© scanned H&E stained slides were reviewed from 230 tumors according to the 2011 IASLC/ATS/ERS lung adenocarcinoma classification criteria. Molecular profiling was performed on 230 resected, untreated lung adenocarcinomas, using mRNA, miRNA and DNA sequencing integrated with copy number, methylation and proteomic analyses. Histologic molecular correlations focused on mRNA and DNA sequencing and TTF-1 proteomic findings.

    Results
    We found 12 lepidic predominant ADC (5%), 21 papillary predominant (9%), 77 acinar predominant (33%), 33 micropapillary predominant (14%), and 58 solid predominant (25%) as well as, 9 invasive mucinous (4%), and 20 unclassifiable ADCs (9%). EGFR mutation and KRAS mutations were found in 8% and 17% of lepidic ADC, respectively. Nine of 12 lepidic ADC (75%) were of the terminal respiratory unit (TRU) gene expression subtype (GES) and 3 (25%)were in the 19p-depleted transcriptional GES, but none were found in the solid-enriched GES (Figure; p=0.007). Most of the papillary ADC were of the TRU (10/21, 47.6%) and 19p-depleted transcriptional (9/21, 42.9%) GES (p=0.026). 46% (41/89) of acinar ADC tumors were in the TRU-GES compared to the solid enriched (18/78, 23.1%) and 19p-depleted transcriptional (18/63, 28.6%) GES (p=0.005). When the oncogene positive group was defined including KRAS, EGFR, ALK, RET, ROS1, BRAF, ERBB2, HRAS and NRAS, there was a higher percentage of solid ADC in the oncogene negative (30/93, 32.3%) compared to the oncogene positive group (28/137, 20.4%, p=0.046). The highest percentage of solid ADC was found in the solid-enriched GES (47/78, 47.4%) compared to the 19p-depleted transcriptional (17/63, 27%) and TRU GES (4/89, 4.5%) (p<0.001). Invasive mucinous ADC correlated with KRAS (but no EGFR) mutations (67%) compared to other ADC (28%, p=0.02) and also lacked elevation of TTF-1 (p=0.007). GES was associated with histologic grade: high grade with solid-enriched GES and intermediate/low grade with TRU GES (p<0.001). Figure 1

    Conclusion
    Our data reveal multiple correlations between molecular (mutation and GES) and histologic (subtyping and grade) features. This reveals insights into the biology of these tumors in particular genetic characteristics of the high grade tumors which may lead to better understanding of why these are more aggressive tumors.