IMMUNOHISTOCHEMISTRY, CYTOKERATIN 7

The IHC – Cytokeratin 7 (CK7) test is an immunohistochemistry-based diagnostic assay used to detect Cytokeratin 7 protein expression in tissue samples. CK7 is an intermediate filament protein found in the epithelial cells of several organs, including the lungs, breast, ovary, endometrium, pancreas, bile ducts, and urinary tract.

This test is widely used in surgical pathology and oncology to identify the origin of epithelial tumors and differentiate between various types of carcinomas. CK7 expression patterns, especially when interpreted together with CK20, help pathologists determine whether a cancer is primary or metastatic and identify its likely site of origin.

Benefits of the Test

• Helps identify the origin of epithelial tumors
• Assists in diagnosing adenocarcinomas and carcinomas
• Supports differentiation between primary and metastatic cancers
• Improves tumor classification accuracy
• Helps guide oncology treatment planning

Why Doctors Recommend This Test

Doctors recommend the IHC CK7 test when there is suspicion of epithelial cancers or metastatic tumors of unknown primary origin. It is commonly used in:

• Diagnosis of lung adenocarcinoma
• Breast cancer evaluation
• Ovarian and gynecological tumor assessment
• Pancreatic and biliary tract cancer investigation
• Identification of metastatic carcinomas

CK7 is frequently used with markers such as CK20, TTF-1, PAX8, GATA3, ER, PR, and CDX2 to create a comprehensive immunohistochemical profile and accurately determine tumor origin.

Preparation Before Test

No special preparation is required for this test. Important considerations include:

• The test is performed on a biopsy or surgical tissue sample
• No fasting or medication restrictions are needed
• Clinical history, imaging findings, and pathology reports may assist interpretation

Normal Reporting Time

The typical turnaround time is 3 to 5 working days, depending on specimen processing and laboratory workflow.

Who Should Take This Test

• Patients with suspected epithelial cancers
• Individuals with adenocarcinoma diagnosis
• Cases of metastatic tumors with unknown primary origin
• Patients undergoing tumor biopsy evaluation
• Oncology patients requiring immunohistochemistry profiling

The IHC CK7 test is an essential diagnostic tool in modern pathology and oncology. By identifying Cytokeratin 7 expression patterns, it helps clinicians determine tumor origin, classify cancers accurately, and develop effective treatment strategies.

Clinical Significance

CK7 is commonly expressed in:

• Lung adenocarcinoma
• Breast carcinoma
• Ovarian carcinoma
• Endometrial carcinoma
• Pancreatic adenocarcinoma
• Cholangiocarcinoma (bile duct cancer)
• Urothelial carcinoma

The CK7/CK20 staining pattern is one of the most widely used approaches for identifying the primary site of metastatic carcinomas.