Genetic markers of colonic neoplasia

IL-10 and sIL-2R serum levels as possible peripheral blood prognostic markers in the passage from adenoma to colorectal cancer

The pathogenesis of cancer is currently under intense investigation to identify reliable prognostic indices for the early detection of disease. Adenomas have been identified as precursors of colorectal cancer and tumor establishment, and disease progression has been found to reflect a malfunction of the immune system. We previously indicated the investigation of cytokine serum levels in these patients as a useful and non-invasive tool for the study of the disease progression and an imbalance at TH1 and TH2 cell levels was also found. Moreover, the soluble form of interleukin (IL) 2 receptor (sIL-2R) level is an in vivo marker of T cell activation and is used to monitor the activation of the immune system. We therefore performed an immunological study on a group of healthy subjects, subjects with adenomas, and colorectal cancer patients to identify peripheral blood invasiveness markers in the progression from normal mucosa through adenoma to tumor. In this paper we evaluated the relationships between serum levels of interleukin IL-2, sIL-2R, interferon (IFN) gamma, IL-4, IL-6, IL-10 and sICAM-1 and their networks. Our overall data indicate that in the normal mucosa through adenoma to tumor progression, the host immune response proceeded from a TH1 cell-mediated immune response type (healthy subjects) to a type with TH2 suppressive characteristics (adenoma subjects and cancer patients). However, in the adenoma subjects there was no IL-10 or sIL-2R involvement, while these parameters were implicated in the cancer patients' immune responses. Moreover, a concurrent augmentation of sIL-2R and IL-10 levels seems to be prognostic for the passage from adenoma to cancer, and the sIL-2R and sICAM-1 molecules appear to be involved in the invasiveness mechanisms.

The study of markers of biological effect in cancer prevention research trials

Biological markers may provide a valuable tool for the development of cancer prevention agents, for monitoring patient compliance to a selected intervention, or for further defining the carcinogenic process. This discussion focuses on markers of biological effect and the rationale for their use in cancer prevention trials. Recent studies with biological markers are investigating their incorporation into phase-I, -II, and -III chemoprevention clinical trial designs. Their use in clinical studies is expected to increase the number of agents that may be evaluated and to provide valuable information on the biological effectiveness of agents, doses, and schedules. Markers may also provide information to help in selecting high-risk groups for prevention research, and to indicate the pathways inhibited and the stage of carcinogenesis affected. Such information may prove of crucial importance in strengthening the rationale for long-term trials and other ancillary research. Biomarker research for colon carcinogenesis is discussed, including examples of a number of recent trials that may influence future progress in this area of prevention research. A crucial step in this process is marker validation as an aspect of major prospective observational and intervention studies where cancer incidence is the endpoint. We cannot be fully confident of markers as intermediate endpoints until the evidence from clinical trials is sufficiently strong to support major public health initiatives for prevention.

Current status of tumor markers in large bowel cancer

The aim of a primary screening system is to detect premalignant lesions and carcinomas when amenable to "curative" surgery. Although a number of "classical" tumor markers have acquired potential for clinical management, none is presently adequate for presymptomatic diagnosis or screening. In colorectal carcinoma, the screening potential of carcinoembryonic antigen (CEA), the gastrointestinal-related antigen, CA19-9, and other more recently characterized "biochemical markers" is virtually nonexistent, even in patients at high risk to develop the disease. Promising new leads are beginning to emerge from somatic cell genetic and molecular biological approaches. In common with other epithelial neoplasms, perturbations in oncogene expression have been demonstrated in colorectal cancers, and probably reflect important events in malignant transformation and progression. Studies of oncogene expression have, however, not yet yielded clinically useful information. Recently, an intensive search for specific chromosomal and gene abnormalities in the hereditary colon cancer syndromes led to the location of the familial adenomatous polyposis (FAP) gene at chromosome 5q21-q22. Significant is that the loss of alleles on chromosome 5 has also been observed in the tumor cells of at least 20% of sporadic colon cancer patients. This type of association between constitutional genetic change and genetic aberration in the cells of sporadic tumors is reminiscent of other malignant diseases with a genetic component (e.g., retinoblastoma and Wilms' tumor).(ABSTRACT TRUNCATED AT 250 WORDS)