Molecular classification of nonsmall cell lung cancer using a 4-protein quantitative assay.
BACKGROUND
The importance of definitive histological subclassification has increased as drug trials have shown benefit associated with histology in nonsmall-cell lung cancer (NSCLC). The acuity of this problem is further exacerbated by the use of minimally invasive cytology samples. Here we describe the development and validation of a 4-protein classifier that differentiates primary lung adenocarcinomas (AC) from squamous cell carcinomas (SCC).


METHODS
Quantitative immunofluorescence (AQUA) was employed to measure proteins differentially expressed between AC and SCC followed by logistic regression analysis. An objective 4-protein classifier was generated to define likelihood of AC in a training set of 343 patients followed by validation in 2 independent cohorts (n = 197 and n = 235). The assay was then tested on 11 cytology specimens.


RESULTS
Statistical modeling selected thyroid transcription factor 1 (TTF1), CK5, CK13, and epidermal growth factor receptor (EGFR) to generate a weighted classifier and to identify the optimal cutpoint for differentiating AC from SCC. Using the pathologist's final diagnosis as the criterion standard, the molecular test showed a sensitivity of 96% and specificity of 93%. Blinded analysis of the validation sets yielded sensitivity and specificity of 96% and 97%, respectively. Our assay classified the cytology specimens with a specificity of 100% and sensitivity of 87.5%.


CONCLUSIONS
Molecular classification of NSCLC using an objective quantitative test can be highly accurate and could be translated into a diagnostic platform for broad clinical application.
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA. valsamo.anagnostou@yale.edu
Valsamo K
VK
Anagnostou
Anastasios T
AT
Dimou
Taxiarchis
T
Botsis
Elizabeth J
EJ
Killiam
Mark D
MD
Gustavson
Robert J
RJ
Homer
Daniel
D
Boffa
Vassiliki
V
Zolota
Dimitrios
D
Dougenis
Lynn
L
Tanoue
Scott N
SN
Gettinger
Frank C
FC
Detterbeck
Konstantinos N
KN
Syrigos
Gerold
G
Bepler
David L
DL
Rimm
D000230:Adenocarcinoma / Q000737:chemistry / Q000145:classification; D000077192:Adenocarcinoma of Lung; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000737:chemistry / Q000145:classification* / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000737:chemistry / Q000145:classification; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D016015:Logistic Models; D008175:Lung Neoplasms / Q000737:chemistry / Q000145:classification* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011506:Proteins / Q000032:analysis*; D046888:Tissue Array Analysis
D011506:Proteins