Thyroid is a small gland in the throat that looks very similar to the butterfly and some special cells in the thyroid produce Calcitonin hormone. Primarily thyroid helps to produce several hormones which help in varied purposes in the human body. The presence of Calcitonin regulates the calcium levels in the blood and also decreases kidney reabsorption to calcium. One the major disorders of Calcitonin is that this can lead to thyroid cancer. When there is excessive amount of calcitonin produced, two conditions arise that are C-cell hyperplasia and medullary thyroid cancer. The C-cel hyperplasia is the initial stage of thyroid disorder and this may or may not lead to medullar thyroid cancer. Medullar thyroid cancer is infectious disease that can spread beyond thyroid disrupting other parts of the body.