Methods and compositions involving microRNA

A method for identifying a human patient as having a marker correlated with cancer based on an increase in miR-21 expression comprising:

• a) obtaining from a patient a breast, colon, lung, thyroid, or bladder tissue sample comprising cells suspected of being cancerous;
• and,
• b) identifying the patient, based on a determination of the tissue sample, as i) having a marker correlated with cancer if there is an increase in miR-21 expression in the tissue sample compared to a noncancerous tissue of the same type as the tissue sample or ii) as not having a marker correlated with cancer if the increase fails to be detected.

A method for identifying a human patient as having a marker correlated with breast cancer based on an increase in miR-21 expression comprising:

• a) obtaining from a patient a breast tissue sample comprising cells suspected of being cancerous;
• and,
• b) identifying the patient, based on a determination of the tissue sample, as i) having a marker correlated with breast cancer if there is an increase in miR-21 expression in the tissue sample compared to a noncancerous tissue of the same type as the tissue sample or ii) as not having a marker correlated with cancer if the increase fails to be detected.