TODAY 8a: TODAY Exclusive — breast cancer breakthrough? Lady A on new album. Chrissy Teigen on past year and new cookbook.

<p>A TODAY exclusive — details on a vaccine trial to prevent one of the most aggressive forms of breast cancer. Plus, Lady A is in Studio 1A! All about their new album and much more. Also ahead, Chrissy Teigen opens up to Hoda Kotb after a year of challenges and is cooking up orange chicken fried sandwiches.</p>