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.

[EX Q]: Question: Is cytoglobin upregulated by tumour hypoxia and silenced by promoter hypermethylation in head and neck cancer?
Answer: We conclude that the CYGB gene is regulated by both promoter methylation and tumour hypoxia in HNSCC and that increased expression of this gene correlates with clincopathological measures of a tumour's biological aggression.
[EX A]: yes

[EX Q]: Question: Does [ Edaravone protect hearing from acute acoustic trauma in guinea pigs ]?
Answer: The level of ROS in cochlea were decreased significantly after intratympanic edaravone injection. The mechanism may due to its effective clearance of the ROS in cochlea.
[EX A]: yes

[EX Q]: Question: Are cholangiocarcinoma in primary sclerosing cholangitis : K-ras mutations and Tp53 dysfunction implicated in the neoplastic development?
Answer: We conclude that K-ras mutations and p53 dysfunction are implicated in tumorigenesis of cholangiocarcinomas arising in PSC patients and that these abnormalities together with increased Ki-67 index may indicate neoplastic progression of bile ducts in these patients.
[EX A]:
yes