# Peritoneal infection after colorectal cancer surgery induces substantial alterations in postoperative protein levels: an exploratory study

## TL;DR

This study finds that peritoneal infection after colorectal cancer surgery leads to significant changes in protein levels, which may explain increased cancer recurrence and cardiovascular issues.

## Contribution

The study identifies specific proteins and pathways altered by peritoneal infection that may underlie increased cancer and cardiovascular risks.

## Key findings

- 77 proteins were differentially expressed in patients with peritoneal infection compared to controls.
- Altered proteins were linked to cancer progression, survival, and cardiovascular pathways.
- Protein levels normalized one year after surgery.

## Abstract

Peritoneal infection, due to anastomotic leakage, after resection for colorectal cancer have been shown to associate with increased cancer recurrence and mortality, as well as cardiovascsular morbidity. Alterations in circulating protein levels could help shed light on the underlying mechanisms, prompting this exploratory study of 64 patients operated for colorectal cancer with anastomosis.

Thirty-two cases who suffered a postoperative peritoneal infection were matched with 32 controls who had a complication-free postoperative stay. Proteins in serum samples at their first postoperative visit and at one year after surgery were analysed using proximity extension assays and enzyme-linked immunosorbent assays. Multivariate projection methods, adjusted for multiple testing, were used to compare levels between groups, and enrichment and network analyses were performed.

Seventy-seven proteins, out of 270 tested, were differentially expressed at a median sampling time of 41 days postoperatively. These proteins were all normalised one year after surgery. Many of the differentially expressed top hub proteins have known involvement in cancer progression, survival, invasiveness and metastasis. Over-represented pathways were related to cardiomyopathy, cell-adhesion, extracellular matrix, phosphatidylinositol-3-kinase/Akt (PI3K-Akt) and transforming growth factor beta (TGF-β) signaling.

These affected proteins and pathways could provide clues as to why patients with peritoneal infection might suffer increased cancer recurrence, mortality and cardiovascular morbidity.

The online version contains supplementary material available at 10.1007/s00423-024-03451-4.