OBJECTIVE: Few investigations on the potential role of IGF-I in human breast cancer have used morphological criteria, and the data presented on the localisation of IGF-I are controversial. Moreover, little information exists on a potential correlation between local IGF-I and the grade of malignancy or prognostic factors. Therefore, we investigated the immunohistochemical localisation of IGF-I in specimens of human breast cancer tumours of the ductal type, graded as G1/G2 (well-/moderately differentiated, n=115) and G3 (poorly differentiated, n=28). METHODS: IGF-I immunoreactivity was quantified using a scaling from no (-) to numerous (+++) IGF-I-immunoreactive cells. From 29 of the G1/G2 and 17 of the G3 tumours IGF-I was also measured by RIA. Cytosolic oestrogen receptor (ER) and progesterone receptor (PR) levels, and S-phase fraction were established and related to the number of IGF-I-immunoreactive cells. RESULTS: IGF-I immunoreactivity occurred predominantly in ductal epithelial cells. Of G3 tumours, 57% exhibited IGF-I immunoreactivity as compared with 84% of G1/G2 tumours. Correspondingly, the amount of IGF-I measured by RIA was significantly lower in G3 tumours (6.9+/-0.9 ng/g wet weight) than in G1/G2 tumours (10.5+/-1.1 ng/g wet weight) (P=0.031). G1/G2 tumours exhibited a higher percentage of IGF-I-immunoreactive cells (16% -, 23% +, 41% ++, 20% +++) than G3 tumours (43% -, 37% +, 12% ++, 8% +++). When comparing the - with the +++ G1/G2 tumours, the frequency of IGF-I-immunoreactive cells was related significantly to the ER (P<0.016) and the PR (P<0.008) levels. In G1/G2 and G3 tumours, the ER and PR levels increased with the amount of IGF immunoreactivity while the S-phase fraction increased with decreasing IGF-I content. In 25% of the specimens, IGF-I immunoreactivity occurred in stromal cells, but there was no obvious difference between the different types of tumours. The survival of the G1/G2 tumour patients increased with increasing numbers of IGF-I-immunoreactive cells. CONCLUSIONS: It is concluded that IGF-I is associated with the more-differentiated type of epithelial cells and that increasing dedifferentiation goes along with decreased IGF-I content. Thus, the presence of IGF-I immunoreactivity in breast cancer epithelial cells indicates a lower degree of malignancy than the lack of IGF-I.
E Eppler, J Zapf, N Bailer, UG Falkmer, S Falkmer and M Reinecke
A. L. Hulting, U. Askensten, B. Tribukait, J. Wersäll, G. Auer, L. Grimelius, S. Falkmer and S. Werner
DNA patterns were analysed in 26 GH-producing pituitary adenomas by flow cytometry as well as by microspectrophotometry. Twelve tumours (46%) were diploid according to both methods, whereas 5 tumours (19%) showed aneuploid DNA patterns. Nine tumours were classified differently by the two methods: flow cytometry resulted in diploidy in 2 and aneuploidy in 7 patients, whereas microspectrophotometry showed diploidy in 5 tumours, tetraploidy in 3 and aneuploidy in 1. Methodological limitations may explain the discrepancy in the results obtained by the two methods. However, both the flow cytometry and the microspectrophotometry method show the presence of aneuploid DNA patterns in GH-producing pituitary adenomas despite their benign growth characteristics and the clinically benign course of the disease. This comparative study with two methods measuring DNA content, shows that depending on the criteria used for diploidy-aneuploidy, the freqency of aneuploidy will vary. In this material of 26 GH-producing adenomas, 46% were aneuploid according to flow cytometry and 23% according to microspectrophotometric. However, no correlation to tumour size or GH levels was found with either method when patients with aneuploid and diploid tumours were compared. Therefore, no clinial significance can so far be drawn from these results.