Springer Online Journal Archives 1860-2000
Conclusions Examination of a relatively small subset of information pertaining to colon tumors indicates that examples in each category (including predisposing markers of chromosomal instability, causally relevant markers, correlation between karyotypic atypia and biological malignancy, and some tumors with no detectable chromosome changes) can all be found. This discussion began with questions about the purposes that markers could serve: some of those questions with reference to colon tumors can be answered. For the most part, the presence of chromosomal aberrations can indeed distinguish between the normal and the tumor cell and, in this sense, help to define the tumor. Moreover, some specific chromosomal alterations appear to be preferentially associated with colon tumors. If the specificity can be better defined, then, like the other specific tumor-chromosome associations, those in colonic mucosa may help to identify and localize gene functions important in the growth, development, or regulation of this specialized tissue. In any event, chromosomal aberrations are of value, not only in confirming the diagnosis, but also by their associations with different behavioral patterns in both malignant and premalignant lesions. Their definition, therefore, may have predictive value for the individual patient. In particular, inability to find such alterations, while it is not evidence of a nontumorous state, in a known malignancy may at least contribute some information about the biology of that particular tumor. The second question was whether markers could be of value in identifying stages in the evolution from a normal to a tumor cell. From the work done thus far on chromosomal instability, it appears likely, when more data are accumulated and the appropriate tests can be standardized, that proof of chromosomal instability may indeed constitute a marker for certain specific tumor-predisposing states. Similarly, the oncogenes, whose normal genomic counterparts are clearly responsible for important functions relating to cell growth and regulation, may prove to be markers for only a limited number of tumors. However, their definition and the resultant contributions to understanding the basic cellular biology of normal and tumor cells should make it possible to identify some of the critical steps that are altered in the multiple pathways leading to tumor.
Type of Medium: