ABSTRACT
Improved staging in all forms of gastro intestinal cancers is a desirable task because many of these cancers are understaged even after curative surgical resection. Indeed, early dissemination of isolated tumour cells is a frequent characteristic of epithelial tumours. The present work at detection of these micrometastatic cells in BM of colorectal cancer [CRC] patients using flow cytometry and immunocytochemistry on mononuclear cells [MNC] and on bone marrow [BM] smears, and comparing the results of the 3 techniques. Presence of micrometastasis was assessed using monoclonal antibody [MoAb] against intracellular cytokeratin 18. the material of the study consisted of 40 cases of CRC constituting the subjects of the study, 28 of them with no overt metastasis while the remaining 12 patients expressed overt metastasis. The results of the cases revealed the following: 1. Using flow cytometry the mean number of micrometastatic cells detected was much higher than those detectd by immunocytochemistry on BM and MNC. 2. The presence of positive micrometastasis was 70% with flow cytometry and 69.2% with immunocytochemistry on BM smear and 50% on MNC. 3. All cases having macrometastasis were positive for micrometastasis using the 3 techniques. In cases showing no overt metastasis, more than half of the patients [57%] were positive for micrometastasis using flow cytometry and a nearly similar% age [55%] with immunocytocemistry on BM smear, while only 37% of these cases had micrometastasis with immunocytochemistry on MNC. As regards the comparison between the 3 techniques, we found that nearly all positive cases by flow cytometry were positive by immunocytochemistry on BM smear except for 2 cases, while only 17 cases were positive by immunocytochemistry on MNC out of 22 cases positive by flow cytometry. Thus flow cytometry can be considered a more sensitive technique, followed by immunocytochemistry on BM smear. Immunocytochemistry on MNC revealed no positive cells at all when applied on negative control cases, while 30% of the cases showd moderately staining cells when using immunocytochemistry on BM smear. Also 20% of negative control cases showed low positivity with flow cytometry. Thus immunocytochemistry on MNC can be considered less sensitive but more specific than the 2 other methods