Test Catalog

Test ID: MESOF    
Mesothelioma, CDKN2A FISH, Tissue

Useful For Suggests clinical disorders or settings where the test may be helpful

Aiding in the diagnosis of mesothelioma by detecting a neoplastic clone associated with deletion involving the CDKN2A gene region at 9p21.

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

This test includes a charge for application of the first probe set (2 fluorescence in situ hybridization probes) and professional interpretation of results. Additional charges will be incurred for application of all reflex probes performed. Analysis charges will be incurred based on the number of cells analyzed per probe set. If no cells are available for analysis, no analysis charges will be incurred.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Interpretation Provides information to assist in interpretation of the test results

A neoplastic clone is detected when the percent of cells with an abnormality exceeds the normal cutoff. In the proper clinical and histologic context, a positive result may support a diagnosis of mesothelioma. However, homozygous loss of CDKN2A can be identified in many neoplasms. Therefore, clinical and pathologic correlation are required. 


A negative result suggests no deletion of the CDKN2A gene region at 9p21. However, as homozygous deletion is not present in all mesotheliomas, this result does not exclude the diagnosis of malignant mesothelioma. In addition, due to limitations of the technology, fluorescence in situ hybridization cannot detect all CDKN2A deletions.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This test is not approved by the U.S. Food and Drug Administration, and it is best used as an adjunct to existing clinical and pathologic information.


Fixatives other than formalin (eg, Prefer, Bouin's) may not be successful for fluorescence in situ hybridization (FISH) assays, however nonformalin-fixed samples will not be rejected.


Paraffin-embedded tissues that have been decalcified are generally unsuccessful for FISH analysis. The pathologist reviewing the hematoxylin and eosin-stained slide may find it necessary to cancel testing.

Supportive Data

Fluorescence in situ hybridization analysis was performed on 44 formalin-fixed, paraffin-embedded tissue samples including 35 with atypical mesothelioma and 9 with typical mesothelioma. The normal controls were used to generate a normal cutoff for this assay. A deletion of CDKN2A was identified in 7 of the 9 typical mesothelioma (77%) and 2 of 35 atypical mesothelioma (5.7%) specimens.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Illel P, Ladanyl M, Rusch V, Zakowski MF: The use of CDKN2A deletion as a diagnostic marker for malignant mesothelioma in body cavity effusions. Cancer. 2003;99:51-56

2. Chiosea C, Krasinkas A, Cagle P, Mitchell KA, Zander DS, Dacic S: Diagnostic importance of 9p21 homozygous deletion in malignant mesotheliomas. Mod Pathol. 2008;21:742-747

3. Hwang H, Pyott S, Rodriguez S, et al: BAP1 immunohistochemistry and p16 FISH in the diagnosis of sarcomatous and despoplastic mesotheliomas. Am J Surg Pathol. 2016;40:714-718

4. Krasinskas A, Bartlett D, Cieply K, Dacic S: CDKN2A and MTAP deletions in peritoneal mesotheliomas are correlated with loss of p16 protein expression and poor survival. Mod Pathol. 2010;23:531-538

5. Singhi A, Krasinskas A, Choudry H, et al: The prognostic significance of BAP1, NF2, and CDKN2A in malignant peritoneal mesothelioma. Mod Pathol. 2016;29:14-24

6. Monaco S, Shuai Y, Bansal M, Krasinskas AM, Dacic S: The diagnostic utility of p16 FISH and GLUT-1 immunohistochemical analysis in mesothelial proliferations. Am J Clin Pathol. 2011;135:619-627

7. Wu D, Hiroshima K, Yusa T, et al: Usefulness of p16/CDKN2A Fluorescence in situ hybridization and BAP1 immunohistochemistry for the diagnosis of biphasic mesothelioma. Ann Diagn Pathol. 2017;26:31-37