AUTHOR=Green Danielle E. , Jayakrishnan Thejus T. , Hwang Michael , Pappas Sam G. , Gamblin T. Clark , Turaga Kiran K. 

TITLE=Immunohistochemistry – Microarray Analysis of Patients with Peritoneal Metastases of Appendiceal or Colorectal Origin

JOURNAL=Frontiers in Surgery

VOLUME=1

YEAR=2015

URL=https://www.frontiersin.org/journals/surgery/articles/10.3389/fsurg.2014.00050

DOI=10.3389/fsurg.2014.00050

ISSN=2296-875X

ABSTRACT=<p><bold>Background:</bold> The value of immunohistochemistry (IHC)-microarray analysis of pathological specimens in the management of patients is controversial, although preliminary data suggest potential benefit. We describe the characteristics of patients undergoing a commercially available IHC-microarray method in patients with peritoneal metastases (PM) and the feasibility of this technique in this population.</p><p><bold>Methods:</bold> We retrospectively analyzed consecutive patients with pathologically confirmed PM from appendiceal or colorectal primary who underwent Caris Molecular Intelligence<sup>™</sup> testing. IHC, microarray, FISH, and mutational analysis were included and stratified by Peritoneal Carcinomatosis Index (PCI) score, histology, and treatment characteristics. Statistical analysis was performed using non-parametric tests.</p><p><bold>Results:</bold> Our study included 5 patients with appendiceal and 11 with colorectal PM. The median age of patients was 51 (IQR 39–65) years, with 11 (68%) female. The median PCI score of the patients was 17 (IQR 10–25). Hyperthermic intra-peritoneal chemoperfusion was performed in 4 (80%) patients with appendiceal primary tumors and 4 (36%) with colorectal primary. KRAS mutations were encountered in 40% of appendiceal vs. 30% colorectal tumors, while BRAF mutations were seen in 40% of colorectal PM and none of the patients with appendiceal PM (<italic>p</italic> = 0.06). IHC biomarker expression was not significantly different between the two primaries. Sufficient tumor for microarray analysis was found in 44% (<italic>n</italic> = 7) patients, which was not associated with previous use of chemotherapy (<italic>p</italic> &gt; 0.20 for 5-FU/LV, Irinotecan and Oxaliplatin).</p><p><bold>Conclusion:</bold> In a small sample of patients with PM, the feasibility and results of IHC-microarray staining based on a commercially available test is reported. The apparent high incidence of the BRAF mutation in patients with PM may potentially offer opportunities for novel therapeutics and suggest that IHC-microarray is a method that can be used in this population.</p>