Cell cycle responses of heterogeneous human colon adenocarcinoma subpopulations to X-irradiation

Comparison of basic fibroblast growth factor levels in clone A human colon cancer cells in vitro with levels in xenografted tumours

We measured levels of basic fibroblast growth factor (FGF-2) in human colon cancer cells (clone A) in vitro and in xenografted solid tumours using a commercial enzyme-linked immunoassay. In Vitro, levels in unfed plateau phase or exponentially growing cells were low, averaging respectively about 2 and 8 pg 10(-6) cells. However, when solid tumours (average volumes 787 mm3) were cut into halves and either enzymatically disaggregated to obtain a cellular fraction or extracted in toto, levels were much higher. In the cellular fraction, values averaged 110 pg 10(-6) cells, while in whole tumour extracts, average values were 24 pg mg-1 tumour tissue. These results indicate that growth factor levels in solid neoplasms may differ markedly from those predicted from in vitro measurements. We hypothesise that the apparent increase in FGF-2 levels in vivo results primarily from the presence of a significant fraction of host cells (in particular, macrophages, which may contain high levels of FGF-2) within xenografted clone A neoplasms.

The clinical significance of regional variations in histologic differentiation within carcinomas of the colorectum

The clinical significance of the presence or absence of regional variations in histologic differentiation within a primary colorectal carcinoma was investigated in this study. Regional variations in histologic differentiation were judged to be present when the low power field of a microscope was occupied by cancer tissue cytologically and architecturally different from that of the surrounding area. Regional variations in histologic differentiation were noted in 153 (42%) of 368 primary carcinomas. Carcinomas with regional variations were of an anaplastic histologic type and had a higher incidence of lymph node metastasis and a worse prognosis than those without regional variations. Thus, the histologic diversity within a carcinoma is thought to be important for determining the prognosis of patients with colorectal cancer.