Diagnosing whether a subject has, or is at risk for developing, pancreatic cancer or pancreatic acinar cell carcinoma, involving measuring the level of the microRNA (miRNA) gene in a test sample.

A method of isolating an miRNA sample from skin comprising applying an adhesive tape to a target area of the skin in a manner to isolate an epidermal sample, where the epidermal sample contains miRNA, where the tape comprises a rubber adhesive, and where the tape is pliable, thus isolating an epidermal sample adhering to the adhesive tape.

A method of reducing the amount of an miRNA in a cell in a subject for treating, e.g., hemolytic anemia, arthrogryposis complex congenita, pituitary ectopia, rhabdomyolysis or hyperkalemia by administering an antagomir to the subject, where the oligonucleotide agent is substantially single-stranded.

A new array of oligonucleotide probes comprising probes that selectively bind a mature mRNA and a platform on which the probes are immobilized; useful for identifying miRNAs in a sample.

An miRNA search method involving determining the base sequence data of a stem loop structure extracted from nucleic-acid-base sequence data, which becomes the base-sequence candidate of an miRNA.

A method of detecting the tissue origin of cancer comprising contacting a sample derived from a sample containing tumor cells with detection probe, which is a member from a collection of detection probes, the collection of detection probes being capable of specifically identifying target RNA sequences in all miRNAs of the mammal.

A nanoparticle useful for detecting an analyte molecule, e.g., miRNA, comprising a transition metal oxide and a capping agent having a ligand group and a functional group.

A microarray for miRNA detection comprising a capture probe of endogenic low–molecular weight RNA. The microarray enables comprehensive and efficient analysis and detection of miRNA and can correctly track time-dependent expression change of miRNA by conducting a relative miRNA expression analysis.

A method of inhibiting the effects of miRNA and/or small interfering RNAs (siRNAs) on gene expression that comprises providing to a system a protein which comprises a sequence of 140 amino acids (SEQ ID NO: 1; A-AC4) or 100 amino acids (SEQ ID NO: 2; S-AC4).

A method of purifying mature miRNAs comprises lysing the sample, degrading the additional nucleic acids and liberating the mature miRNAs.

Diagnosing a biological condition, e.g., cancer, comprising amplifying a target miRNA from a test sample to provide a derived miRNA quantity, where the target miRNA is from a tissue of interest, comparing the derived miRNA quantity to an expectation miRNA quantity from a background tissue, and diagnosing the biological condition.