Early detection of malignant pleural mesothelioma in asbestos-exposed individuals with a noninvasive proteomics-based surveillance tool.
BACKGROUND
Malignant pleural mesothelioma (MM) is an aggressive, asbestos-related pulmonary cancer that is increasing in incidence. Because diagnosis is difficult and the disease is relatively rare, most patients present at a clinically advanced stage where possibility of cure is minimal. To improve surveillance and detection of MM in the high-risk population, we completed a series of clinical studies to develop a noninvasive test for early detection.


RESULTS
We conducted multi-center case-control studies in serum from 117 MM cases and 142 asbestos-exposed control individuals. Biomarker discovery, verification, and validation were performed using SOMAmer proteomic technology, which simultaneously measures over 1000 proteins in unfractionated biologic samples. Using univariate and multivariate approaches we discovered 64 candidate protein biomarkers and derived a 13-marker random forest classifier with an AUC of 0.99±0.01 in training, 0.98±0.04 in independent blinded verification and 0.95±0.04 in blinded validation studies. Sensitivity and specificity at our pre-specified decision threshold were 97%/92% in training and 90%/95% in blinded verification. This classifier accuracy was maintained in a second blinded validation set with a sensitivity/specificity of 90%/89% and combined accuracy of 92%. Sensitivity correlated with pathologic stage; 77% of Stage I, 93% of Stage II, 96% of Stage III and 96% of Stage IV cases were detected. An alternative decision threshold in the validation study yielding 98% specificity would still detect 60% of MM cases. In a paired sample set the classifier AUC of 0.99 and 91%/94% sensitivity/specificity was superior to that of mesothelin with an AUC of 0.82 and 66%/88% sensitivity/specificity. The candidate biomarker panel consists of both inflammatory and proliferative proteins, processes strongly associated with asbestos-induced malignancy.


CONCLUSIONS
The SOMAmer biomarker panel discovered and validated in these studies provides a solid foundation for surveillance and diagnosis of MM in those at highest risk for this disease.
Clinical Research, SomaLogic Inc., Boulder, Colorado, United States of America. rostroff@somalogic.com
Rachel M
RM
Ostroff
Michael R
MR
Mehan
Alex
A
Stewart
Deborah
D
Ayers
Edward N
EN
Brody
Stephen A
SA
Williams
Stephen
S
Levin
Brad
B
Black
Michael
M
Harbut
Michele
M
Carbone
Chandra
C
Goparaju
Harvey I
HI
Pass
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001194:Asbestos; D014408:Biomarkers, Tumor / Q000097:blood; D002273:Carcinogens; D016022:Case-Control Studies; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D037102:Lectins / Q000097:blood; D008297:Male; D008654:Mesothelioma / Q000139:chemically induced / Q000175:diagnosis* / Q000378:metabolism; D008875:Middle Aged; D010997:Pleural Neoplasms / Q000139:chemically induced / Q000175:diagnosis* / Q000378:metabolism; D025341:Principal Component Analysis; D040901:Proteomics / Q000379:methods*; D062486:Public Health Surveillance / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult; D000097604:Ficolins
D001194:Asbestos; D014408:Biomarkers, Tumor; D002273:Carcinogens; D037102:Lectins; D000097604:Ficolins