This breath test has detected cancers at a stage when they CAN be seen on Xrays or looking in with cameras. However the larger the cancer ultimately the worse it is for the patient. It would therefore be much better to have the breath test find patients with cancers at a much smaller size. It is interesting that the cancers which the breath test HAVE found all have the same breath test signal, regardless of size. This means even smaller cancers may have the same signal. These small cancers are only 1-2 mm thick, and when found at this size almost all can be cured. We want to find a group of patients who have these early cancers and compare it to breath test result in patients who have large obvious cancers. These patients will be compared to other patients who have are negative for larynx cancer who also have a breath test. We want to prove that their breath test will be negative.