Tumor Budding Versus Mismatch Repair Status in Colorectal Cancer – An Exploratory Analysis

BACKGROUND: Tumor budding and a proficient mismatch repair (pMMR) status are considered adverse prognostic factors in colorectal cancer (CRC). The aim of this pilot study was to assess tumor budding in primary CRC with pMMR versus that with deficient mismatch repair (dMMR). MATERIALS AND METHODS: Tumor budding was retrospectively examined in the tumor from 134 patients with stage II and stage III CRC with known MMR status. The 29 available dMMR cases who developed recurrence or distant metastases (met+) were matched with a dMMR group with no recurrence or metastases (met-), and the pMMR/met+ group with pMMR/met- cases. RESULTS: Using tumor budding cut-offs of 5 and 10, a significantly higher percentage of high-grade tumor budding (≥5 and ≥10) was only found in the dMMR/met+ compared to pMMR/met+ subgroup (p=0.01 and p=0.02, respectively). CONCLUSION: A significantly higher grade of tumor budding was observed in the dMMR/met+ group, suggesting that tumor budding can provide prognostic information for patients with a dMMR status.