Next, we aimed to identify molecular subtype-specific miRNAs.
However, to do so, a larger repository of molecular subtype-specific miRNA expression is required.
The identification of several molecular subtype-specific miRNAs in this study also suggests that blood tests directed at the molecular subtypes can be developed in the future.
In both lung carcinoma subtypes, there was a large variation in ELF5 levels, suggesting possible molecular subtype-specific expression patterns, similar to the breast.
Therefore, we correlated the molecular subtype-specific miRNA-expression profiles of each sample with each of the five miRNA-based expression centroids by using the Spearman correlation coefficient.
Further evidence that the applied normalization procedure did not obscure molecular subtype-specific differences is derived from the UHCA, which showed that the molecular subtypes govern global themes in our miRNA expression data set.
Further, we compared the gene-expression features of each molecular subtype to specific time points in models of airway development.
Recent large-scale breast cancer genome studies have revealed that each molecular subtype has specific pattern of genomic alterations and notably, tumors of HER2-enriched and basal-like subtypes harbor many more rearrangements than the luminal A subtype, which primarily consists of receptor positive breast tumors [ 2].
As previously suggested, we found that basal-like, ERBB2+, luminal A, and luminal B molecular subtypes displayed specific methylation profiles.
Although 4 major molecular subtypes in specific geographic areas have been described, epidemiologic and clinical associations have been best documented for the HTLV-1a subtype, which predominates in the Caribbean region and Japan.
We believe that the baseline will still be traditional histopathology combined with clinical staging, but with a second layer of molecular classification with subtype specific prognostic and predictive tests.
