Abnormal p53 staining patterns (strong/diffuse or null) were observed in six of 12 (50%) myxoid and six of 11 (55%) conventional leiomyosarcomas but none of the IMT (P < 0.0001), correlating with TP53 mutation/deletion (P = 0.0001).
We have reported that mesenchymal stromal/stem cells (MSCs) deficient for p53 alone or together with RB (p53(-/-)RB(-/-)) originate leiomyosarcoma after subcutaneous (s.c.) inoculation.
(2) Coincidental p53 allele mutation and PML loss shifts the tumor profile toward sarcoma formation, which is paralleled in human leiomyosarcomas (indicated by immunohistochemistry; IHC).
Conversely, p53 null mutations (frameshift, splice sites, nonsense) and mutations outside the DNA-binding domain were associated with leiomyosarcoma (OR, 10.1; 95% CI, 3.4-29.9), a type of sarcoma that occurred after age 20 years.
The p53 and phosphoinositide-3-kinase, catalytic, alpha polypeptide/v-akt murine thymoma viral oncogene homolog/mechanistic target of rapamycin (PIK3CA/AKT/mTOR) pathways frequently are altered in sarcoma with complex genomics, such as leiomyosarcoma (LMS) or undifferentiated pleomorphic sarcoma (UPS).
These results suggest that the loss of RB and P53 may have contributed to the initiation and/or progression of the leiomyosarcoma of the bladder in this patient.
Our results indicate that p53 abnormalities are major events and that an increasing level of p53 mRNA is associated with an overexpression of p53 protein in leiomyosarcoma and they may play an important role in the tumorigenesis in this tumor.
Restoration of wt p53 expression in human leiomyosarcoma SKLMS-1 cells that contain mutant p53 markedly inhibited angiogenesis induced by tumor cells in vivo.
According to our results, p53 protein nuclear expression was detected in 20% (8/40) of the tumours (1 fibrosarcoma, 2 liposarcomas, 1 leiomyosarcoma, 1 rhabdomyosarcoma, 2 Ewing's sarcomas and 1 unclassified sarcoma).
In this study, we analyzed cell proliferating factors (mitotic and Ki-67 indices) and the p53 status of both types of leiomyosarcoma (37 cases) to evaluate the possibility that these factors may serve as indicators in prognosis.
Overexpression of p53 was seen in 17 (55%) of 31 sarcomas, including 9 (64%) of 14 malignant fibrous histiocytomas, 4 (44%) of 9 rhabdomyosarcomas, and 4 (50%) of 8 leiomyosarcomas.
In contrast, p53 gene mutations were detected at a lower frequency in malignant fibrous histiocytomas (2/34 cases) and not at all in nine chondrosarcomas and five leiomyosarcomas.
In this study we analysed immunohistochemically 63 mesenchymal tumours for the expression of bcl-2 and p53 proteins with a special emphasis on muscle-derived tumours. bcl-2 was expressed in all seven rhabdomyosarcomas and in five out of seven leiomyosarcomas.
It was suggested that P53 over-expression might be associated with the transformation of leiomyoma into leiomyosarcoma and could be used as an objective parameter in distinguishing the malignant from the benign and predicting the prognosis of patients with smooth muscle tumors of the gastrointestinal tract.
In addition, we have demonstrated a significant association between the presence of abnormalities of the p53 gene or MDM2 genes in leiomyosarcomas and a more advanced clinicopathological stage (P = 0.03).