Granzyme B, Is it a Cause for Clinical Paradox in Medullary Breast Carcinoma?

Medullary carcinoma of the breast is a unique sub-type of infiltrating ductal carcinoma that is characterized by a prominent lymphoid infiltrate and improved prognosis. Cytotoxic T lymphocyte with positive granzyme-B constitutes a major subset within the lymphoid infiltrate. Granzyme B has been reported to be involved in suppression of cancer progression. The aim was to study the relationship between Granzyme B expression and medullary carcinoma behavior. Twenty six female patients included in the study at Dr. Soliman Fakeeh Hospital and Al Hay at Hospital, Jeddah, K.S.A. between March 2004 to January 2007, there were sixteen below 45 years and ten above 45 years, Granzyme. B were positive in 75% of the first group and 60% positive in the second group. Gr. B expression was positive in 62.5% of cases with tissue diagnosis of IDC accompanied by in situ component while it was 80% when the diagnosis was IDC only. Gr B expressed in 100% of cases of medullary carcinoma, and 60% in others. This difference in expression was highly significant (P .001). This was also associated with lesser lymph node affection in cases diagnosed as medullary carcinoma. It was 4 out of six while in others it was 18_ out of 20 with non significant statistical difference. Granzyme-B +ve cytototic T- lymphocytes were 100% in medullary carcinoma while Granyme-B +ve tumor cell was 33.3% only. On the other hand the values were 60% and 20% in others. NO showed 100% +ve Granzyme-B, N1 showed 71.4% and N2 showed 50%. Conclusion: Granzyme B through induction of apoptosis is an important mechanism governing tumour progression and improved prognosis in medullary carcinoma of the breast. Granzyme B in a way or another is responsible for damaging cancer cells, leading to lost ability to invade lymphatic vessels or to grow in regional lymph nodes.