Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:These results are in accordance with previous studies suggesting that miR-let7a may act as a tumor suppressor (it is poorly expressed in lung and colon cancer) [38, 39] and its downregulation has been reported to have a prognostic impact on the survival of surgically treated lung cancer patients [38].
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