CD71 is useful in identifying erythroid precursors with no interference from mature erythrocytes and also in the determination of erythroid leukemia, benign erythroid proliferative disorders, and myelodysplastic syndrome.
CD79a first appears at the pre B-cell stage and persists until the plasma cell stage where it is found as an intracellular component. CD79a is found in the majority of acute leukemias of precursor B-cell type, B-cell lines, B-cell lymphomas, and in some myelomas. It is not present in myeloid cells or T-cells.
CD8 is a T-cell marker for the detection of cytotoxic/suppressor T-cells. CD8 is also detected on NK cells, most thymocytes, a subpopulation of null cells, and bone marrow cells. This antibody is useful in evaluating T-cell lymphomas.
CD99 (MIC2 gene product, E2) antigen is strongly expressed by Ewing sarcoma cells, primitive peripheral neuroectodermal tumors, and lymphoblastic leukemia/lymphoma.
Among cyclin/CDK proteins, CDK4 and cyclin D1 are the most frequently activated by somatic genetic alterations in multiple tumor types. CDK4 antibody assists in distinguishing atypical lipomatous tumor well-differentiated liposarcoma (WDL) (positive) from benign adipocytic neoplasms (negative).
CDX2 is an intestine specific transcription factor that regulates both the proliferation and differentiation of intestinal epithelial cells. It is expressed in the nuclei of epithelial cells throughout the intestine, from duodenum to rectum. The CDX2 protein is expressed in primary and metastatic colorectal carcinomas and has also been demonstrated in the intestinal metaplasia of the stomach and intestinal-type gastric cancer. It is not expressed in the normal gastric mucosa. CDX2 may be used in identifying metastatic carcinoma of colonic or other gastrointestinal tract origin in the setting of an unknown primary tumor.
Carcinoembryonic antigen (CEA) is usually demonstrated as a linear labeling of the apical poles of cells lining the glandular lumen and occasionally as weak staining near the apex of normal colonic epithelial cells. Tumors tend to display an increased cytoplasmic staining. In specific cases, CEA can be useful in tumor diagnosis. Pancreatic carcinomas, testicular tumors, gallbladder neoplasms and granular cell myoblastomas all stain positive for CEA, while malignant tumors of brain, prostate, skin, lymphoreticular tissues, hepatocellular carcinomas, esophageal squamous cell carcinomas and mesothelioma fail to stain for CEA.
Polyclonal carcinoembryonic antigen (CEA) antibody stains a larger percentage of cholangiocarcinomas compared to hepatocellular carcinomas. Approximately 95% of cholangiocarcinomas are stained diffusely and strongly with polyclonal CEA, whereas show a canalicular staining pattern with this antibody.
Testing is done via bi-directional sequencing of the relevant coding region and fragment analysis for detection of sequence variant and internal tandem duplication mutations.
Chromogranin is present in several elements of the diffuse neuroendocrine system (DNES), including anterior pituitary, thyroid perifollicular C cells, parathyroid chief cells, pancreatic islet cells, intestinal enterochromaffin cells and tumors derived from these cells. Chromogranin immunoreactivity was also seen in thymus, spleen, lymph nodes, fetal liver, neurons, the inner segment of rods and cones, the submandibular gland and the central nervous system. This marker is useful in evaluating neuroendocrine tumors.