Given the task definition and input, reply with output. Given a passage with a question and an answer to that question, classify if the answer actually answers the question into 'yes' or 'no'. Output 'yes' if the answer answers the question and output 'no' if the answer does not answer the question.

Question: Does platelet-derived growth factor expression correlate with tumor grade and proliferative activity in human oligodendrogliomas?
Answer: The results of this study showed that MIB-1 LI is a rapid and cost-effective modality for predicting tumor grade in oligodendrogliomas. Immunohistochemistry for PDGF was found to be useful in differentiating various grades of oligodendroglioma, and therefore, it may be involved in tumor cell proliferation and malignant transformation. Platelet-derived growth factor receptor alpha, although expressed in oligodendroglial neoplasms, was not found to be useful in predicting tumor grade.
yes