Methods for lung cancer classification
The present invention provides specific nucleic acid sequences for use in the identification, classification and diagnosis of various sub-types of lung cancers. The present invention permits one to accurately classify lung cancers based on their miR expression profile without further manipulation. Using microRNA microarray data generated from over two hundred formalin-fixed paraffin-embedded (FFPE) resection samples, fine needle aspiration (FNA) samples and fine needle biopsy (FNB) samples of primary lung cancer, microRNA expression profiles were identified that differ significantly for various sub-types of lung cancer.
1. A method for classifying a lung cancer as a subtype selected from the group consisting of squamous cell carcinoma, non-squamous non-small cell lung cancer (NSCLC), carcinoid lung cancer, and small cell lung carcinoma, the method comprising: providing RNA obtained from a lung cancer sample from a human subject in need thereof; determining an expression profile of nucleic acid sequences comprising SEQ ID NOS: 1-8 in said lung cancer sample, wherein the expression profile is determined by nucleic acid amplification comprising contacting the RNA of said lung cancer sample with forward primers comprising SEQ ID NOs: ii and 12; using a classifier algorithm to compare said expression profile to a training data set comprising expression levels of SEQ ID NOs: 1-8 determined in diagnosed lung cancers from each of said lung cancer subtype; wherein the comparison of said expression profile to said training data set assigns said lung cancer sample to one of said subtypes of lung cancer; and classifying said lung cancer sample into one of said subtypes based on said comparison.
2. The method of claim 1 , wherein relatively high expression levels of SEQ ID NOS: 3, 7, and 8 as compared to said training data set, is indicative of carcinoid lung cancer.
3. The method of claim 1 , wherein relatively high expression levels of SEQ ID NO: 1 as compared to said training data set, is indicative of small cell lung cancer (SCLC).
4. The method of claim 1 , wherein relatively high expression levels of SEQ ID NOS: 2, 5, and 6 as compared to said training data set, is indicative of non-squamous non-small cell lung cancer (NSCLC).
5. The method of claim 1 , wherein relatively high expression levels of SEQ ID NO: 4 as compared to said training data set, is indicative of squamous cell carcinoma.
6. The method of claim 1 , wherein said lung cancer sample is selected from the group consisting of bodily fluid and a tissue sample.
7. The method of claim 6 , wherein said tissue is a fresh, frozen, fixed, wax-embedded or formalin fixed paraffin-embedded (FFPE) tissue.
8. The method of claim 1 , wherein the nucleic acid amplification method is real-time PCR.
9. The method of claim 8 , wherein the real-time PCR method further comprises reverse primers.
10. The method of claim 9 , wherein the forward primers further comprise a sequence selected from the group consisting of SEQ ID NOS: 9, 10, and 13-16.
11. The method of claim 10 , wherein the real-time PCR method comprises at least one probe.
12. The method of claim 11 , wherein the probe comprises a sequence selected from the group consisting of any one of SEQ ID NOS: 17-24.
13. The method of claim 1 , wherein the classifier algorithm is K-nearest neighbor.