Sven Olaf Frahm

Minichromosome Maintenance Protein (MCM6) in Low-Grade Chondrosarcoma Distinction From Enchondroma and Identification of Progressive Tumors

The distinction between chondrosarcoma and enchondroma is difficult, and no reliable immunohistochemical or molecular methods are available. Differentiation is important because the therapeutic consequences range from radiologic follow-up to radical operation. We studied 17 chondrosarcomas (12 grade 1) and compared them with 14 enchondromas immunohistochemically by using the monoclonal antibodies Ki-MCM6 (minichromosome maintenance protein 6), Ki-S5 (Ki-67), and Ki-S2 (repp86), in addition to the established clinical criteria. In comparison with the other markers, Ki-MCM6 proved more effective at identifying proliferative activity in grade 1 chondrosarcomas. The MCM6 labeling index correlated with tumor grade and was significantly increased in grade 1 chondrosarcomas compared with enchondromas. The 5 cases of progressive chondrosarcoma also had a significantly higher MCM6 labeling index than the nonprogressive cases. Furthermore, by means of the MCM6 labeling index, many cases of progressive disease were recognized among those of uncertain malignant potential, justifying their classification as low-grade chondrosarcomas.

Ki-Mcm6, a new monoclonal antibody specific to Mcm6 : Comparison of the distribution profile of Mcm6 and the Ki-67 antigen

Ki-Mcm6, a New Monoclonal Antibody Specific to Mcm6: Comparison of the Distribution Profile of Mcm6 and the Ki-67 Antigen

Telomere shortening in uterine leiomyomas.

OBJECTIVE To gain a better understanding of proliferation control mechanisms in a common benign tumor, we investigated the mean telomere length and the clonality of uterine leiomyomas. STUDY DESIGN Deoxyribonucleic acid from uterine leiomyomas and from the adjacent normal myometrium of 51 patients (total number of uterine leiomyomas 107; 28 patients with single leiomyoma, 23 patients with multiple leiomyomas ranging from 2 to 8 myoma nodules per case) was hybridized to a telomeric oligonucleotide probe by Southern blot and chemiluminescent detection. The mean telomere length was evaluated by densitometry. Clonality was assessed with use of the phosphoglycerokinase gene polymorphism. RESULTS The mean telomere length was significantly shorter in uterine leiomyomas (median 7950 bp, interquartile range 7261 to 8372 bp) than in normal myometrium (median 9688 bp, interquartile range 8528 to 10535 bp) (P < .001). There was no correlation between tumor size and telomere attrition. Multiple uterine leiomyomas were found to have an independent clonal origin. CONCLUSIONS Telomere attrition in uterine leiomyomas reflects enhanced proliferation activity in the course of tumor evolution. The basic telomere lengths differ in the myocytes from which the uterine leiomyomas originate, probably explaining the lack of correlation between telomere attrition and tumor size.