Question

Question (1) Provide mechanistic interpretations for the relatively longer survival of melanoma patients, who also suffer from the condition of pigment loss from the skin known as vitiligo, than melanoma patients who do not suffer from vitiligo.

Question (2) Describe concisely the priority sequence of the overall cancer control strategies as well as the steps to take and goal to achieve for each of the strategies.

Answer 1

Melanoma that is associated with vitilago is an example of linkage b/w autoimmunity and tumor immunity. Vitilago is an autoimmune disorder that is associated with the destruction of melanocytes, and it serves as a independent positive prognostic for melanoma patients. This autoimmune killig of melanoocyte maintains T cell immunity to melanoma. Melanoma is outgrowth of melanocytes which turns into an aggressive cancer. But development of melanoma in certain patients along with vitilago spontaneously regresses the primary tumor that is vitilago turns out to be a portended improved prognosis for patients of melanoma. In this way these patients survival was prolonged indicating the relationship between the 2 disorders. In 1983 it was demonstrated by Nordlund and colleagues that there is approx 5 years enhanced survival rate in melanoma patient also suffering from vitilago.

In later years with more research and discoveries the mechanism linking the two phenomena came into light. Melanoma associated with vitilago was a result of cross reactive immune response. It was the immunological mechanism which results in regression of primary melanomas directly implied to antitumor immunity. Currently on the basis of latest discoveries 2 mechanisms are proposed by scientist for vitilago pathogenesis.

1. Antibody based
2. T cell based

Autoantibodies that recognizes tyrosine (TRP 1 and TRP 2), are observed in sera of vitilago and melanoma patients. Antibodies found in sera of the patients of vitilago have been shown to lyses melanoma and melanocytes cells. if we compare the patients of vitilago to the melanoma patients with vitilago, the latter have similar titers of antibody to TRP 2.

In the next mechanism, melanoma cells were killed by CD8 T cells taken from vitilago patient’s lesion. And CD8 T cells taken from melanoma patients have also been shown to kill normal melanocytes. Using the observation identical T cells were found in melanoma patients with vitilago, surrounding depigmented lesions. Therefore, this significant evidence supported the theory that melanoma patients with vitilago enhance the patients life by CD8 T cells mediated phenomenon.