In theory it shouldn't matter as long as the methodology is robust, the data collection was unbiased (as little as possible, if any it is declared), and the conclusions are sound and humility is shown in reference to the hypothesis. Typically you'll see papers with a section toward the end where researchers will declare any financial backing or conflicts of interest arising from the research (PLOS is one journal that I think has a mandatory field for this). tl;dr don't dismiss something just because the source may be biased.