Arrest of Cell Proliferation in Budding Tumor Cells Ahead of the Invading Edge of Colonic Carcinomas. A Preliminary Report

Abstract

Background: Single or small groups of dedifferentiated tumor cells, referred to as tumor budding, may be found ahead of the defined invasive edge of colorectal carcinomas. Tumor budding is claimed to correlate with lymph node metastasis and local recurrence. Materials and Methods: Sections from six surgically removed invasive colonic carcinomas were stained with hematoxylin-eosin (H&E), MNF 116 (an epithelial marker) and for Ki-67 (a proliferation marker) and four specimens also for laminin-5 (a cell-locomotion marker). Results: In comparative fields, a mean of 86.2 tumor buds (range 60-132) were detected with MNF 116 immunostain, 5.8 tumor buds (mean, range 5-9) with H&E stain, 9.7 tumor buds (range 7-18) with Ki-67 immunostain and 9.3 tumor buds (range 8-12) with laminin-5. Conclusion: The majority of the MNF 116-positive budding tumor cells ahead of the invading tumor front were not detected with H&E, or for Ki-67 or laminin-5. Host invasion by budding tumor cells might be activated only after the cell cycle has been switched off (G0).