Author of

• 15382

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  P3.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 235)

  • Event: WCLC 2015
  • Type: Poster
  • Track: Biology, Pathology, and Molecular Testing
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/09/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)

  • 15389

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    P3.04-007 - EML4/ALK Status in Lung Cancer - A 2 Year Experience from a Tertiary Care Cancer Centre in India (ID 2400)

    09:30 - 09:30  |  Author(s): T.S. Rao
    • Abstract

    Background:
    Detection of EML4-ALK rearrangement in lung cancers has influenced the diagnosis and management of a subset of patients with advanced adenocarcinoma. It has become pertinent that all ethnic groups are evaluated for ALK status. Since there is only one published study of EML4/ALK status ( Desai et al, 2013) from India, we sought to analyse the frequency of ALK positivity and correlation of this gene rearrangement with different parameters (age, gender and morphologic subtypes etc.).
    
    Methods:
    A retrospective analysis of data on ALK gene rearrangement status in lung cancer patients from the archives of the Department of Pathology & Laboratory Medicine was done over a period of 2 years( between March 2013 to March 2015) as per the ASCO / CAP/ IASLC guidelines 2013. Majority of the assays were done by Fluorescence in situ hybridization (FISH) using the Vysis ALK Breakapart rearrangement probe ( Abbott Molecular Inc). Immunohistochemistry was done with ALK D5F3 clone (Ventana). The morphology was reviewed by two pathologists trained in pulmonary pathology. Statistical analysis was performed to assess the impact of age, gender and morphologic subtypes on ALK positivity.
    
    Results:
    Of the 217 cases of adenocarcinoma of lung diagnosed in the Pathology department, 16 patients were excluded from the study. Two hundred and one patients underwent assay for ALK gene rearrangement. The assay was done by FISH in 181 patients(90%) and IHC in 20 patients(9.95%). The male to female ratio was 1.25:1. The tissue submitted for analysis comprised of lung tissue in 138 patients (68.7 %) and tissue from metastatic sites in 63 patients (31.34%). The most common metastatic siteswere lymph nodes 30 (47.61) and skeletal metastases 10 (15.87%). Of these, ALK was positive in 16 cases (7.96%) and negative in 185 patients( 92.03% ). All cases detected to be positive for ALK by either method (FISH/IHC) were confirmed by the other methodology inhouse.The major morphologic subtypes included acinar predominant 99 (49.25%),solid predominant 36 (17.91%),mucinous 16 (7.96%) and lepidic predominant 15(7.46%). Of the 99 (47.76%) cases, TTF 1 expression was seen in 89 cases (92.07%). ALK positivity was seen in 10 female patients (62.5%) as opposed to 79(42.7%) females lacking ALK rearrangement. ALK positive patients were younger ( median 41 years) among females when compared to ALK negative women ( median 54.5 years). ALK positive males were also younger( median 50 years) when compared to negative cases (median 60 years). Stratifying the ALK status in relation to age groups in increments of 10 years showed that 68.7% of the ALK positive patients were below the age of fifty years when compared to 27% of ALK negative cases. Statistical analysis showed that younger age (p= 0.0143) and female preponderance (p=0.0251) were statistically significant in the ALK positive subset. A specific predilection towards morphology could not be established. Acinar subtype constituted the majority of all subtypes 8/16 (50%)
    
    Conclusion:
    Increased frequency of ALK positivity in lung adenocarcinoma (7.96%) was noted in comparison to earlier published data .ALK D5F3 assessment by IHC may prove to be a cost effective alternative for analysis