ObGyn Doctor Explains: Hereditary breast and ovarian cancer and gene mutations

A Japanese Obstetrician Gynecologist is talking about the following topics:
Q What is cancer?
Q What is hereditary cancer?
Q What is hereditary breast and ovarian cancer syndrome?
Q Who should be tested for BRCA mutations?
Q What is genetic counselling?
Q How is the test for BRCA mutations carried out?
Q What does a negative test result mean?
Q What does an unclear test result mean?
Q What does a positive test result mean?
Q What can I do to prevent cancer if I test positive for a BRCA mutation?