Genomic instability in giant cell tumor of bone. A study of 52 cases using DNA ploidy, relocalization FISH, and array‐CGH analysis

Abstract

Genetic instability in relation to clinical behavior was studied in 52 cases of giant cell tumor of bone (GCTB). Ploidy was determined in the mononuclear cell population by using native cell smears and image cytometry. A relocalization technique allowed fluorescent in situ hybridization (FISH) analysis of CD68-negative neoplastic cells for numerical changes of chromosomes X, 3, 4, 6, 11, and telomeric association on 11p. Genome-wide alterations were tested using array comparative genomic hybridization (array-CGH) on magnetically separated CD68-negative tumor cells. CTNNB1, TP53, and BCL2 protein expression was also analyzed in formol-paraffin sections to see if their pathways are involved in the development of chromosomal instability. CD68-positive histiocytes showed no significant numerical chromosome and telomeric alterations. Based on ploidy values and clinical outcome, we could distinguish five groups as follows: diploid nonrecurrent (n = 20), tetraploid nonrecurrent (n = 6), diploid recurrent (n = 5), tetraploid and/or aneuploid recurrent (n = 14), and malignant cases (n = 7). Random individual-cell aneusomy was significantly (P < 0.001) more frequent in the recurrent groups (36.01 +/- 11.94%) than in the benign nonrecurrent cases (10.65 +/- 3.66%). The diploid recurrent group showed significantly (P < 0.001) increased balanced aneusomy compared with the diploid nonrecurrent group and the tetraploid nonrecurrent group represented eusomic polysomy. Array-CGH and FISH showed clonal aberrations almost exclusively in the malignant group. None of the protein markers tested showed significant correlation with elevated aneuploidy/polysomy (P = 0.56). Our results show that ploidy determination combined with FISH analysis may help predicting recurrence potential of GCTB and suggest that chromosomal abnormalities superimposed on telomeric associations could be responsible for an aggressive clinical course.

Histological and clinical characteristics of malignant giant cell tumor of bone

“…Eusomic polysomy has been seen in several tetraploid nonrecurrent cases, and balanced aneusomy has been found more frequently in diploid recurrent than in diploid nonrecurrent cases. These findings suggest that chromosomal abnormalities superimposed on telomeric associations might be responsible for the aggressive behavior of GCTB [31]. The expression of proteins involved in cell cycle regulation/oncogenesis, such as p53, p63, ki-67, cyclinD1, or Bcl-2, are not predictive for the clinical behaviour of GCTB [32].…”

A case of secondary malignant giant-cell tumor of bone with p53 mutation after long-term follow-up

“…A p53 mutation has also been reported in bone and soft tissue sarcomas [12]. However, a p53 mutation has rarely been reported in malignant or benign GCT [13,14]. A p53 point mutation as well as p53 overexpression in stromal cells has been reported in a case of recurrent GCT diagnosed as malignant GCT [14].…”

Centrosome abnormalities in giant cell tumour of bone: possible association with chromosomal instability

“…We have previously shown that random aneusomy is a feature of the CD68-negative mononuclear stromal cell population of giant cell tumour of bone, and that this feature correlates with biological aggressiveness, with chromosomal gain and loss turning into clonal but random genetic aberrations in malignant cases. 2 In this study, we show that there is a strong correlation between chromosomal instability and centrosome amplification, suggesting a possible involvement of the latter in generating chromosomal instability in giant cell tumour of bone. However, relocalization studies and immunocytochemistry, in combination with FISH, showed no association between centrosome amplification and chromosome number alteration, indicating that alternative causative mechanisms are responsible for generating genetic instability in giant cell tumour of bone.…”

“…24 Membrane and cytoplasmic expression of CTNNB1, a member of the Wnt signalling pathway, has been observed in giant cell tumour of bone; although the failure of this signalling route (usually with the nuclear accumulation of CTNNB1) is well known to cause aneusomies and tetrasomies, 25 no significant correlation has been observed between CTNNB1 positivity and the degree of aneusomy in giant cell tumour of bone, or between CTNNB1 expression and giant cell tumour of bone recurrence. 2,26 One of the most commonly observed genetic aberrations in giant cell tumour of bone is telomeric association. Telomeric association alone, however, does not have a role in the development of genetic instability.…”

“…1 The mixed mononuclear cell population in giant cell tumour of bone includes both reactive CD68-positive macrophages and proliferating stromal cells. 2,3 Recently, it was shown that the rate of chromosomal aneusomy in the CD68-negative stromal cell population is higher in recurrent compared with nonrecurrent giant cell tumour of bones; chromosomal aneusomy was found to be clonal in most malignant cases of giant cell tumour of bone, suggesting that chromosomal instability may be responsible for aggressive behaviour. 2 Possible mechanisms that might contribute to chromosomal instability in giant cell tumour of bone include loss of mitotic checkpoint function, defective kinetochore function and abnormal amplification of centrosomes.…”