Clinicopathological correlations of Bcl-xL and Bax expression in differentiated thyroid carcinoma.

OBJECTIVE: The Bcl-2 family proteins are essential mediators in the apoptotic process. Our aim was to investigate whether anti-apoptotic Bcl-xL and pro-apoptotic Bax were over-expressed in a large series of differentiated thyroid carcinomas (DTC) and to study their association with tumour presentation at diagnosis and prognosis. DESIGN AND PATIENTS: We examined the immunohistochemical expression of Bcl-xL and Bax in benign nodular thyroid disease (BNTD) and DTC and their association with clinicopathological parameters. Thyroid tissue samples were collected from an unselected series of patients undergoing surgical resection for DTC (n = 74) or BNTD (n = 15). RESULTS: Among DTC cases, expression of Bcl-xL was found to be high in 43.2% and low or absent in 56.8%. Expression of Bax was high in 75.7% and low or absent in 24.3%. Non-neoplastic thyroid tissue was largely unstained for both proteins. Among BNTD cases, expression of Bcl-xL was high in 13.3% and low or absent in 86.6%. Expression of Bax was high in 14.3% and low or absent in 86.6%. A significant association was found between Bcl-xL expression and the presence of high-risk histological subtype (P < 0.05), and regional lymph node (P < 0.01) and distant metastases (P < 0.01). The association between high Bcl-xL expression levels and a longer time of persistent disease after radioiodine ablation was also significant (P < 0.01). Bcl-xL expression was confirmed as an independent prognostic factor for persistent disease in DTC (relative risk, 2.5; 95% confidence interval, 1.1-5.9; P < 0.05). CONCLUSIONS: Immunohistochemical expression of Bcl-xL might be a valuable tool in the prediction of tumour aggressiveness in DTC.

Comparative study of the immunohistochemical phenotype in breast cancer and its lymph node metastatic location.

At present, an important part of prognostic information, together with particular treatment strategies in breast cancer, take into account the immunohistochemical phenotype of the primary tumor location. However, the changing heterogeneity intrinsic to neoplastic cells in general leads us to consider the possibility that the expression of these proteins is modified during tumoral development and dissemination. With this hypothesis as a starting point, 60 patients with breast cancer were studied with immunohistochemistry, the expression of estrogen and progestagenic receptors, proliferation through the Ki-67 expression, and the overexpression of HER-2 and p53 in both the primary location and the lymph node metastases. If we consider significant change to be loss (from positive to negative) or gain (negative to positive) of expression in some of the studied determinations, we find that this is produced in 60% of the tumors studied. These results demonstrate the modification of immunohistochemical expression of the proteins studied between the primary tumor location and the lymph node metastases.