The invention provides methods of diagnosing whether a subject has, or is at risk for developing, lung cancer, comprising measuring the level of at least one miR gene product in a test sample from said subject, wherein an alteration in the level of the miR gene products in the test sample, relative to the level of corresponding miR gene products in a control sample, is indicative of the subject either having, or being at risk for developing, lung cancer. The invention also provides methods of diagnosing whether a subject has, or is at risk for developing, lung cancer, comprising: reverse transcribing RNA from a test sample obtained from the subject to provide a set of target oligodeoxynucleotides； hybridizing the target oligodeoxynucleotides to a microarray comprising miRNA-specific probe oligonucleotides to provide a hybridization profile for the test sample； and comparing the test sample hybridization profile to a hybridization profile generated from a control sample, wherein an alteration in the signal of at least one miRNA is indicative of the subject either having, or being at risk for developing, lung cancer. The at least one miR gene product is selected from the group consisting of miR-21, miR-191, miR-155, miR-210, miR-126* and miR-224.
