Chemotherapy of colorectal liver metastases induces a rapid rise in intermediate blood monocytes which predicts treatment response.

We have previously reported that intermediate monocytes (CD14(++)/CD16(+)) were increased in colorectal cancer (CRC) patients, while the subset of pro-angiogenic TIE2-expressing monocytes (TEMs) was not significantly elevated. This study was designed to evaluate changes in frequency and function of intermediate monocytes and TEMs during chemotherapy and anti-angiogenic cancer treatment and their relation to treatment response. Monocyte populations were determined by flow cytometry in 60 metastasized CRC (mCRC) patients who received neoadjuvant chemotherapy with or without bevacizumab.

Monocytes with angiogenic potential are selectively induced by liver resection and accumulate near the site of liver regeneration.

Background: Monocytes reportedly contribute to liver regeneration. Three subsets have been identified to date: classical, intermediate, non-classical monocytes. The intermediate population and a subtype expressing TIE2 (TEMs) were suggested to promote angiogenesis.

Intermediate monocytes but not TIE2-expressing monocytes are a sensitive diagnostic indicator for colorectal cancer.

We have conducted the first study to determine the diagnostic potential of the CD14++CD16+ intermediate monocytes as compared to the pro-angiogenic subset of CD14++CD16+TIE2+ TIE2-expressing monocytes (TEMs) in cancer. These monocyte populations were investigated by flow cytometry in healthy volunteers (N = 32) and in colorectal carcinoma patients with localized (N = 24) or metastatic (N = 37) disease. We further determined blood levels of cytokines associated with monocyte regulation.