Pre-treatment miR-205 concentrations were found to be significantly higher in SQCC than in ADC patients, and only SQCC patients presented significantly higher circulating miR-205 levels than healthy donors.
We performed global gene expression profiling and revealed that suppressive functioning of miR-205 in adenocarcinoma could be realized through regulation of epithelial-mesenchymal transition (EMT), whereas oncogenic in squamous cell carcinoma by regulation of metalloproteinase 10.
Examination of publicly available datasets identified miR-205 and miR-375 as microRNAs with the best ability to histotype AC and SCC, and that levels of the two microRNAs in AC or SCC are unaffected by the pathologic stage of the tumor or the age or race of the patient.
Our results indicate that elevated miRNA-205 was significantly associated with enhanced overall survival in the breast cancer subgroup (HR=0.78, 95% CI 0.67 to 0.91) and superior disease-free survival/recurrence-free survival in the adenocarcinoma subgroup (HR=0.68, 95% CI 0.49 to 0.94).
Surprisingly, expression of classifier miR-205 was intermediate between that of classical adenocarcinoma and squamous cell carcinoma suggesting that adenosquamous carcinoma is a transitional stage between these tumor types.
MicroRNA-205 yielded high diagnostic accuracy in discriminating SQ from AC with an area under the curve (AUC) of 0.985, and discriminating SQ from SCLC with an AUC of 0.978 in formalin-fixed paraffin-embedded (FFPE) surgical lung tissues.
Two microRNA panels yielded high diagnostic accuracy in discriminating SCLC from NSCLC (miR-29a and miR-375; area under the curve [AUC], 0.991 and 0.982 for training and validation data set, respectively) and in differentiating SQ from AC (miR-205 and miR-34a; AUC, 0.977 and 0.982 for training and validation data set, respectively) in FFPE surgical lung specimens.
The miR-205 sample score value, determined according to Lebanony et al, was higher in ADC (range, 2.8 to 9.08) compared with SQCC (range, -4.17 to 2.445) (P<0.0001).
Profiling the hsa-let-7 family and hsa-miR-205 is a promising method for differentiating AD from SCC, even in such small specimens as transthoracic aspirates.
A quantitative reverse transcription-PCR diagnostic assay that measures the expression level of hsa-miR-205 was used to classify the carcinomas as SqCC or adenocarcinoma based solely on expression levels.