Development of fetal haemoglobin-blood cells (F cells) within colorectal tumour tissues

To evaluate the sources of fetal haemoglobin (HbF) as an indicator in cancer. An immunohistochemical study was carried out on some of the most common kinds of cancer. All of these cancers had serologically high levels of HbF as evaluated previously.

Immunoaffinity-purified anti-HbF was immunohistochemically used to study F cell distribution in the following cancers: colorectal adenocarcinoma, urinary bladder transitional cell carcinoma, brain tumours, lung carcinoma, breast adenocarcinoma, leukaemia, Burkitt's lymphoma and endometrial carcinoma.

In colorectal adenocarcinoma, HbF-containing red blood cells (FRBC) were present within thin-walled vessels or were disposed in dense clusters within the tumour. Some of these cells were nucleated or binucleated HbF-erythroblasts or HbF-normoblasts (FNBS). In two cases, high levels of mitoses within HbF-erythroblasts were observed. In half of the cases with transitional cell carcinoma of the urinary bladder, regional intratumoral blood vessels were found to contain 5-50% FRBC. In the other tumours examined, F cells were not observed. FRBCs, however, were occasionally observed in the regional lymph nodes of some of these cancers.

The evaluation of HbF as a potential plasma marker is suggested by the high concentration of FRBCs in colorectal tumours. The apparent development of FRBCs in colorectal tumour tissues is an interesting observation, as these cells were previously thought to develop in medullary or lymphoid tissues. It is thus suggested that the colonic microenvironment may stimulate extramedullary fetal-type haematopoiesis.