The critical issue is to select the most appropriate tissue block for immunohistochemical stains. The selected block should contain suffcient amount of tumor tissue with best preserved morphology indicating the best fixation which is often equal to the best preservation of the epitopes. Try to avoid necrotic or degenerated areas and try to include normal tissues which in many cases may serve as positive internal control.
A) Compare results of immunostaining in well preserved (well fixed) and poorly preserved (poorly fixed) areas of the lymph node with metastatic carcinoma of the breast (different parts of the same parafin block).
HE. Metastatic adenocarcinoma of the breast in axillary lymph node. Notice good morphology equal good formalin fixation at lower left corner and effects of delayed/poor fixation in the middle and upper right corner. 4x
HE. Metastatic adenocarcinoma of the breast in axillary lymph node. High magnification from well fixed area (lower left). 40x.
HE. Metastatic adenocarcinoma of the breast in axillary lymph node. High magnification from area with poor morphology (central part). 40x.
E-Cadherin. Metastatic adenocarcinoma of the breast in axillary lymph node. Staining in the area with well preserved morphology. Notice strong membranous staining in tumor cells. 10x.
E-Cadherin. Metastatic adenocarcinoma of the breast in axillary lymph node. Staining in poorly preserved area shows abnormal, predominantly cytoplasmic pattern, absence of convincing membranous staining and positive cytoplasmic staining in macrophages. 10x.
E-Cadherin. Metastatic adenocarcinoma of the breast in axillary lymph node. Transition between well preserved (strong, membranous staining of tumor cells) and poorly preserved morphology (partial membrane reactivity, abnormal cytoplasmic positivity or negative staining). Macrophages show positve cytoplasmic staining. 10x.
Ki67. Metastatic adenocarcinoma of the breast in axillary lymph node. Notice difference in the number of Ki67 positive tumor cells between well fixed area (left) and area with poor fixation (central part and right). 4x.
B) Compare results of immunostaining in two different blocks from solitary fibrous tumor.
CD34. Solitary fibrous tumor of the prostate. Strong staining in the blocks taken from the periphery of the tumor. 10x.
CD34. Solitary fibrous tumor of the prostate. Weakly positive cytoplasmic staining with negative areas in the block taken from the central region of tumor due to suboptimal formalin fixation. Notice that tumor cells do not show any convincing membrane staining, however endothelial cells containing higher concentration of the antigen are strongly positive.
We use cookies to ensure that we give you the best experience on our website. If you continue to use this site we will assume that you are happy with it.
