Analysis of p53 mutational events and MDM2 amplification in canine soft-tissue sarcomas.

Canine cancer is of major significance in terms of animal health and welfare and soft tissue sarcomas are an important group of tumours accounting for approximately 15% of all canine tumours presented. Abnormal p53 protein expression and gene mutations have been identified in a number of different canine tumour types. However, mdm2 gene amplification has only been investigated in a limited number of canine osteosarcomas. In this present study a series of canine soft-tissue sarcomas (STS) were examined for p53 mutations and/or mdm2 amplification. For p53 mutational studies polymerase chain reaction and direct DNA sequencing was used. Gene mutations were identified in 6 of 30 (20%) primary tumour cases including MPNST (n=3) leiomysarcoma (n=1), heamangiosarcoma (n=1) and sarcoma (n=1). mdm2 gene amplification was assessed by Southern Blot. Although there was no evidence for major gene rearrangements, gene amplification was detected in 4 of 35 (11.4 %) primary tumours including MPNST (n=2), rhabdomyosarcoma (n=2). A total of 33 cases were examined for both p53 mutations and mdm2 amplification. Seven of the tumours were positive for p53 mutations, while five were positive for mdm2 amplification. With the exception of one case, a reciprocal relationship between the presence of a p53 mutation and mdm2 gene amplification was demonstrated.     

Primary versus radiation-associated craniofacial osteosarcoma: Biologic and clinicopathologic comparisons

BACKGROUND: Craniofacial osteosarcoma differs from long bone osteosarcoma in that patients are older, tumors are often low grade, and prognosis is more favorable. Although most are sporadic, some tumors occur in association with prior radiation therapy. The purpose of the current study was to compare clinicopathologic and prognostic features of primary and radiation-associated osteosarcoma. METHODS: The study group consisted of 15 primary and 6 radiation-associated osteosarcomas. Clinical and follow-up data were obtained in every case. Tissue microarrays were immunohistochemically stained for p53, pRB, Ki-67 (MIB-1), and ezrin. DNA was sequenced for TP53 mutations. RESULTS: All radiation-associated osteosarcomas were high grade and half were fibroblastic. In contrast, 47% of primary craniofacial osteosarcomas were high grade and only 1 was fibroblastic. All radiation-associated osteosarcomas recurred, half the patients died of disease, 2 were alive with unresectable tumors, whereas only 1 was alive without disease. In contrast, 80% of patients with primary tumors were alive without disease, 33% had local recurrences, and 13% died of disease. Radiation-associated tumors overexpressed p53 more often (33% vs. 13%), more often had TP53 mutations (33% vs. 8%), had higher proliferative activity (67% vs. 0% showing >50% MIB-1 staining), and expressed ezrin more frequently (83% vs. 40%) than primary tumors. Compared with a control group of 24 high- and 7 low-grade primary extremity osteosarcomas, radiation-associated tumors marked as the high-grade tumors. CONCLUSIONS: Craniofacial radiation-associated osteosarcomas are high-grade tumors that behave more aggressively than most primary craniofacial osteosarcomas. In addition, they demonstrate higher expression rates of adverse prognostic indicators, further highlighting the distinction.     

Osteosarcoma arising in Paget's disease of the mandible

Although osteosarcoma is a well-known complication of Paget's disease of bone, it uncommonly develops in the jaw bones. We present an osteosarcoma arising in Paget's disease of the mandible with unique features of a normal serum alkaline phosphatase level, and histologic features of telangiectatic change in the osteosarcoma and association with cemento-osseous dysplasia. Sixteen reported cases of osteosarcoma arising in Paget's disease of the jaw bones (OPJ) are also reviewed and compared to osteosarcoma arising in Paget's disease occurring in the entire skeleton (OPS) and osteosarcoma arising de novo in the jaw bones (OJ). Females are more commonly involved in OPJ in contrast to a male predominance in OPS and OJ. OPJ also has a distinctively higher percentage involving blacks compared to OPS. The prognosis of OPJ is poor, with 69% of patients dying within two years after diagnosis. Early recognition, early and aggressive treatment are important to improve the prognosis and are hence emphasized.     

HER-2/neu and p53 in osteosarcoma: an immunohistochemical and fluorescence in situ hybridization analysis

The overexpression of HER-2/neu and p53 has been associated with poor outcome in many neoplasms. Their role in patients with osteosarcoma is unclear. We studied the expression of HER-2/neu and p53 in 22 osteosarcoma samples (from 20 patients—2 had locally recurrent disease) biopsied at the University of Medicine and Dentistry of New Jersey (UMDNJ) from 1996-2000 using both immunohistochemical (IHC) and fluorescence in situ hybridization (FISH) analysis. Fourteen patients (14 samples) presented with Stage II and 6 patients (8 samples) presented with Stage III disease. Median follow-up is two years (range one year to five years). Four of 22 (18%) samples showed focal membranous or cytoplasmic positivity for HER-2/neu and six of 22 samples (27%) showed nuclear positivity for p53 by IHC analysis. In contrast, none of 22 tested samples showed gene amplification for HER-2/neu by FISH analysis. Seven of 13 HER-2/neu and p53 negative patients (54%) are currently disease free (between one year to five years). In this sample of patients, the HER-2/neu oncogene is not overexpressed or amplified in osteosarcoma; six of 22 samples (27%) showed overexpression of p53 by IHC analysis. By FISH, none of the samples demonstrated deletion of p53. Neither HER2/neu nor p53 expression was important for the biology of osteosarcoma in this population.     

Inactivation of p53 gene in human and murine osteosarcoma cells.

We examined structure and expression of the p53 and Rb genes in a C3HOS transplantable mouse model of osteosarcoma. The results were compared to analogous studies conducted with five human osteosarcoma cell lines. The p53 gene was found rearranged in the mouse tumour. The rearrangement mapped to the first intron region of the p53 gene and as a result, no p53 expression could be detected in C3HOS tumours. Using p53 genomic probes, we have detected the same rearrangement in the original radiation-induced tumour and the various clones that were isolated from it. Deletion and rearrangement of the p53 gene were also found in three out of five of the human osteosarcoma cell lines (MG-63, G-292, Saos-2). No p53 expression could be detected in these three cell lines. In the affected human osteosarcoma cell lines, the rearrangement involved the first intron region. In addition, the mouse tumor was analysed for structural and expression changes in the Rb and the c-myc genes. Normal expression of both genes were detected in the murine tumour. Only one (Saos-2) human osteosarcoma cell line exhibited gross structural alteration in the retinoblastoma gene. The results suggest that the inactivation of p53 may be an important step in the development of osteosarcomas, and that a rearrangement affecting the first intron is common in osteosarcomas.     

Changing metastatic patterns of osteosarcoma

The clinical courses of 111 patients with osteosarcoma treated at UCLA between 1971 and 1982 were reviewed to ascertain the evolution of the natural history of this disease. Only patients with classic high-grade intraosseous osteosarcoma of the extremity, scapula, or pelvis were considered. Patients with low-grade parosteal osteosarcomas; primary osteosarcomas of the face, skull, vertebra, or ribs; and osteosarcomas arising in Paget's disease or previously irradiated bones were not included. Fifty-nine patients developed clinically evident distant metastases. Of these, 36 developed pulmonary metastases alone as the initial site of recurrence. Eighteen of 19 (94.7%) patients treated between 1971 and 1974 by amputation alone developed pulmonary relapse as the initial site of recurrence, whereas only 18 of 40 patients (45%) treated after 1974 with surgery and adjuvant chemotherapy developed pulmonary metastases alone as the initial site of recurrence. Although no patients in the early group developed an extrapulmonary metastasis as the initial site of recurrence, 11 of 40 patients (27.5%) treated with adjuvant chemotherapy developed an extrapulmonary metastasis as the initial site of recurrent disease, and 11 patients developed simultaneous pulmonary and extrapulmonary metastases. Although it is impossible to attribute this alteration in metastatic pattern to adjuvant chemotherapy alone, it is apparent that nonpulmonary metastases are becoming more common among patients currently treated for osteosarcoma.     

Comparison of p53 mutations in patients with localized osteosarcoma and metastatic osteosarcoma

BACKGROUND: In some malignancies, p53 mutations are associated with tumor progression. To address the role of p53 mutations in the development and progression of osteosarcoma, the authors analyzed specimens from 247 patients with primary localized osteosarcomas and 25 patients with osteosarcomas that were metastatic at the time of diagnosis. The group included 27 matched biopsy-resection specimens and 21 biopsy-metastasis paired specimens. METHODS: The authors examined the nature and location of p53 mutations (exons 4-10) by polymerase chain reaction-single-strand conformation polymorphism and confirmed mutations by direct DNA sequencing. RESULTS: The overall frequency of p53 mutations was 22% (60 of 272 specimens), with 13 of 60 mutations located in exons 4 or 10. A similar proportion of localized osteosarcomas had alterations of the p53 gene (55 of 247 specimens; 22.3%) compared with tumors from patients who had metastases at the time of diagnosis (5 of 25 specimens; 20%; P = 0.96). Patients who had p53 missense mutations were older compared with patients who had nonsense alterations or a wild type gene (P = 0.01). Examination of paired biopsy-resection and biopsy-metastasis specimens revealed that the p53 status was concordant between the biopsy and later tumor specimens in all patients. CONCLUSIONS: The p53 mutation status did not differentiate between patients who presented with a localized osteosarcoma and those who presented with metastases at the time of diagnosis. The current data indicate that p53 mutations are not late events in osteosarcoma tumor progression, because they are evident before the development of metastases. The inclusion of exons 4 and 10 increased the sensitivity of the analysis.     

Imaging of bone tumors using a monoclonal antibody raised against human osteosarcoma

The radiolabeled monoclonal antibody 791T/36 raised against a human osteosarcoma was injected into 20 patients with known or suspected bone tumors. Gamma camera images were acquired at 48 or 72 hours after injection, and assessed for antibody localization. Positive images were obtained in all five osteosarcomas and four other primary malignant sarcomas. Two of the four other primary bone tumors gave positive images. Three patients with trauma had negative images as did one patient with Paget's disease. Two patients with suppurative disease gave positive images. The antibody localized in the majority of malignant sarcomas tested. In one tumor where tissue was available, a tumor:non-tumor ratio of 2.8:1 was measured. Repeat imaging was performed in five patients. Immunoscintigraphy using the monoclonal antibody 791T/36 has shown tumor localization in patients with bone and soft tissue sarcomas.     

Telomerase, p53 and PCNA activity in osteosarcoma.

AIMS: The aim of this study was to investigate telomerase activity and to assess the correlation between telomerase activity, tumor proliferative activity and p53 overexpression in osteosarcoma tumor samples. METHODS: Using a telomerase polymerase chain reaction-enzyme-linked immunoassay based on the telomeric repeat amplification protocol method, we examined telomerase activity in 26 primary osteosarcoma specimens. P53 overexpression was identified using immunohistochemical staining, and tumor proliferative activity was assessed by immunohistochemical staining of PCNA. RESULTS: Telomerase activity was detected at a relatively low level in five of 26 osteosarcoma tissue specimens. P53 was detected in eight of 21 cases. There was no significant correlation between telomerase activity and p53 overexpression (p=0.325). There was a significant correlation between PCNA staining and telomerase activity (p=0.0075). CONCLUSION: Difference between the telomerase activity and p53 overexpression in osteosarcoma suggests that p53 and telomerase may not cooperate in tumor proliferation. Correlation of telomerase activity to PCNA expression suggests that telomerase activity may also useful for evaluate proliferative activity in osteosarcoma.     

Genetic alterations in primary osteosarcoma from 54 children and adolescents by targeted allelotyping

At present, the only recognised prognostic factor for primary osteosarcoma is the histological response to preoperative chemotherapy. Our study was designed to identify new diagnostic markers that could eventually have a prognostic value. A total of 54 patients under 20 years of age with primary osteosarcomas were studied while under treatment by the French Society of Paediatric Oncology OS 94 protocol. Paired normal and biopsy samples were collected. In addition, surgical resection specimens, following preoperative chemotherapy, were obtained in 13 cases. After genomic DNA extraction, an allelotyping analysis targeting microsatellites linked to Rb and p53 genes, and 9p21, 7q31 and 5q21 regions was performed. In all, 94% of the samples at diagnosis showed allelic imbalance and the biopsies were highly rearranged except for the microsatellite targeting 7q31. The same panel was highly informative at surgical resection. Microsatellites investigating Rb, p53 and the 9p21 region were particularly altered without a significant correlation with prognosis. On the other hand, the alteration of the 7q31 locus at diagnosis was significantly correlated with a worse prognosis and a new frequently altered locus, 5q21, was described. In conclusion, this panel allowed us to characterise paediatric osteosarcomas. Correlation of prognosis with the altered 7q31 region could be a useful tool and further studies are required to confirm the importance of 5q21.     

Extramammary Paget's disease of the perineal skin: role of radiotherapy.

We have reviewed our treatment results in 65 patients with extramammary Paget's disease arising in the vulva, perianal area, or scrotum. In 30 patients with primary disease, positive surgical margins were found in 53%, and there was an actuarial local recurrence rate of 40% within 5 years. The median follow-up period for primary extramammary Paget's disease patients treated with surgery alone was 198 months, and none died of this disease. Three patients treated with definitive radiotherapy were without recurrence at 12, 21, and 60 months after 56 Gy of supervoltage x-rays. In 22 patients with extramammary Paget's disease and associated adnexal or rectal adenocarcinoma, nine treated with surgery alone had a 75% local control rate. Three patients treated with surgery and adjuvant radiotherapy all had local control; of two patients treated with radiotherapy alone, one had persistent adenocarcinoma. The median survival for all patients with extramammary Paget's disease and adenocarcinoma was 22 months. We conclude that patients with extramammary Paget's disease have excellent survival but that local recurrence and morbidity from surgery, especially in the elderly, can be high. Radiotherapy greater than 50 Gy as primary treatment for extramammary Paget's disease in those medically unfit for surgery, or as an alternative to further surgery for recurrence after surgery and for anyone wishing to avoid mutilating surgery, is indicated. For those with adenocarcinoma and extramammary Paget's disease, the use of adjuvant postoperative radiotherapy in doses greater than 55 Gy is indicated because of the high risk of local recurrence after surgery alone.     

骨肉瘤中Rb、p16、CDK4、cyclinD1蛋白的表达及其意义

目的 探讨骨肉瘤中Ｒｂ、ｐ１６、ＣＤＫ４、ｃｙｃｌｉｎＤ１的蛋白表达、相互关系及其意义。方法 应用免疫组化方法对４０例骨肉瘤组织中Ｒｂ、ｐ１６、ＣＤＫ、ｃｙｃｌｉｎＤ１的蛋白表达状况进行检测。结果 ４０例骨肉瘤Ｒｂ、ｐ１６蛋白表达缺失分别为７２．５％（２９／４０和）２２．５％（９／４０）;１１例ｐＲｂ阳性的骨肉瘤中的８例ｐ１６阴性,２９例ｐＲｂ阴性的骨肉瘤中２８例ｐ１６阳性;５２．５％（２１／４０     

Association of Loss of Heterozygosity at the p53 Locus with Chemoresistance in Osteosarcomas

Although the osteosarcoma is considered to be among the most chemosensitive malignancies and preoperative chemotherapy is commonly applied, an appreciable proportion of cases are in fact quite insensitive. Predictive markers for chemosensitivity are therefore desirable in order to develop effective treatment strategies. Thirty-two cases of conventional osteosarcomas treated at the Cancer Institute Hospital, Tokyo, were analyzed. The sensitivity to preoperative chemotherapy was investigated with reference to loss of heterozygosity (LOH) at the 17p13 ( p 53) and 13q14 ( Rb ) loci and expression of the cell-cycle associated proteins, p53, Rb, p21/Waf-1, mdm-2 and Ki-67, as detected immunohistochemically. LOH was detected by analyzing polymerase chain reaction products at marker microsatellite loci. The efficacy of chemotherapy was evaluated both radiologically and histologically. LOH at p 53 or Rb loci was seen in 54% (13/24) and 58% (14/24) of cases, respectively. Only 15% of osteosarcomas with LOH at the p 53 locus were sensitive to preoperative chemotherapy, as compared to 64% of tumors without such loss ( P <0.05). A similar but much less distinct tendency was observed with LOH at the Rb locus. No relationship was evident between chemosensitivity and immunohistochemical staining patterns for p53, Rb, p21/Waf-1, mdm-2 or Ki-67. The results suggest that p 53 gene deletion, but not the other parameters investigated, may be useful for predicting chemoresistance of osteosarcomas.     

Quantitative assessment of HER2/neu expression by real-time PCR and fluorescent in situ hybridization analysis in low-grade osteosarcoma

Low-grade osteosarcoma is a rare variant of osteosarcoma. Although malignant, it must be distinguished from conventional osteosarcomas because of its excellent prognosis. Numerous published papers have described the expression of HER2/neu oncogene in osteosarcoma as a poor prognostic factor; however their results are discordant. To address the expression of HER2/neu and to validate the assessment methods of amplification of the HER2/neu oncogene, the authors have employed quantitative real-time PCR and fluorencent in situ hybridization analysis (FISH) in 21 low-grade osteosarcomas. We calculated the quantification of HER2/neu oncogene amplification as the ratio of measured HER2/neu gene/beta-globin reference gene in real-time PCR. All 21 cases had amplified signals in the quantitative real-time PCR. However, in the FISH analysis, HER2/neu oncogene amplification was only identified in 26% (5/19). The exact reasons for the discordance between these two methods are unknown; however, variable histological features might play a potential role. In conclusion, as our study showed amplification of HER2/neu oncogene in low-grade osteosarcoma, we assume that expression of HER2/neu is not a poor prognostic factor in low-grade osteosarcoma.     

Amplification of the MDM2 gene in human breast cancer and its association with MDM2 and p53 protein status.

The present study reports on the frequency of MDM2 gene amplification and MDM2 protein expression in a series of 100 breast carcinomas and its association with accumulation of the p53 protein. Of the 100 cases, frozen samples for 82 cases were available for Southern blotting. Three of the 82 (4%) demonstrated MDM2 gene amplification of up to 6-fold. Immunohistochemical analysis of the formalin-fixed, paraffin-embedded tumours demonstrated that 7/97 (7%) had nuclear expression for MDM2 in 10-50% of the tumour cells (type 2 staining) and were denoted MDM2+. Two of the MDM2-amplified samples were MDM2+ with one of the two tumours also displaying type 2 p53 nuclear staining. Finally at the protein level, MDM2+ tumours were significantly associated with tumours having low levels of p53 staining (0-10% cells positive) (P = 0.03). We conclude that MDM2 gene amplification occurs at a lower frequency in breast cancer than in non-epithelial tumours. Alterations in MDM2 and p53 may represent alternative pathways in tumorigenesis, but they are not mutually exclusive in all cases.     

COPS3 amplification and clinical outcome in osteosarcoma

BACKGROUND: Amplification of several genes that map to a region of chromosome 17p11.2, including COPS3, was observed in high-grade osteosarcoma. These genes were also shown to be overexpressed and may be involved in osteosarcoma tumorigenesis. COPS3 encodes a subunit of the COP9 signalosome implicated in the ubiquitination and ultimately degradation of the P53 tumor suppressor. To determine the relation between COPS3 amplification, P53 mutation, and patient outcome in osteosarcoma, tumors from a large cohort of patients with high-grade osteosarcoma and long-term clinical follow-up were examined. METHODS: Quantitative real-time polymerase chain reaction (PCR) was performed to detect copy number changes for COPS3, as well as additional genes (NCOR1, TOM1L2, and PMP22) from the 17p11.2 amplicon, in 155 osteosarcomas from a prospective collection of tumors with corresponding clinical data. Univariate and multivariate analyses were performed to assess differences in survival between groups. RESULTS: Amplification of COPS3, detected in 31% of the osteosarcomas, was strongly associated with large tumor size (P=.0009), but was not associated with age at diagnosis, site, sex, and tumor necrosis. COPS3 amplification was significantly correlated with a shorter time to metastasis with an estimated hazard ratio (HR) of 1.61 (95% confidence interval [CI], 1.02-2.55) in univariate analysis (log-rank test, P=.042). However, in an a priori multivariate Cox model including the other clinical parameters, the HR for COPS3 amplification decreased to 1.32 (95% CI, 0.82-2.13, P=.25), mainly due to the strong correlation with tumor size. COPS3 amplification and P53 mutation frequently occurred in the same tumors, suggesting that these are not mutually exclusive events in osteosarcoma. Although not statistically significant, patients whose tumors exhibited both molecular alterations tended to be more likely to develop metastasis compared with patients with either COPS3 amplification or P53 mutation alone. CONCLUSIONS: COPS3 is the likely target of the 17p11.2 amplicon. COPS3 may function as an oncogene in osteosarcoma, and an increased copy number may lead to an unfavorable prognosis.     

Amplification and protein expression of chromosome 12q13-15 genes in osteosarcomas of the jaws

Overexpression and amplification of several genes (MDM2, CDK4 and SAS) located on chromosome 12q13-15 have been noted to occur in various human sarcomas. As a result, two major growth regulation pathways may be inhibited. MDM2 may down regulate the p53-mediated growth control and CDK4 may affect pRB-mediated events. To determine the frequency of alterations in these genes and their correlation with clinicopathologic features, we analyzed the MDM2 and CDK4 protein levels by immunohistochemistry and assessed MDM2, CDK4 and SAS amplification by real-time PCR in nine osteosarcomas of the jaws. Positive staining for CDK4 and MDM2 was observed in eight cases (88.8%) and five cases (55.5%), respectively. Intense CDK4 staining was noted in four cases (two high grade, one intermediate grade and one low grade). Intense MDM2 staining was observed in the same four previous cases, as well as, one additional high-grade tumor. Individual DNA amplification for CDK4, MDM2 and SAS was observed in six cases for each gene. Co-amplification was observed in five cases that showed CDK4 and MDM2 concomitant amplification and four cases that displayed amplification for all of the genes. In addition, among the five cases that presented CDK4 and MDM2 amplification, strong overexpression of CDK4 and MDM2 was observed in three and in four cases, respectively (three high grade and one intermediate grade). These results suggest that 12q13-15 genes are involved in neoplastic disease and concurrent amplification and overexpression of these genes might help to define high-grade tumors.     

Paget's Osteosarcoma - no Cure in Sight

Purpose Paget' s osteosarcoma has a fearful reputation with a quoted survival of at best 5% at 5 years.We therefore reviewed our experience of 26 patients treated over the last 25 years using modern staging and limb salvage techniques to see if there had been any improvement in survival. Subjects: We identified 26 patients on the Royal Orthopaedic Hospital Oncological database with a diagnosis of sarcoma secondary to Paget's disease.Results: The survival rate was 53% at 1 year, 25% at 2 years and no patient survived for 5 years.The median survival was 21 months for those treated with curative intent and 7 months for those treated palliatively. Four of the five patients treated with limb-sparing surgery developed local recurrence between 5 and 12 months, the fifth died at 14 months.There was no difference in survival between amputation and limb salvage.Discussion: The development of sarcomatous change in Paget's disease is well recognised. It represents an important segment of primary bone tumours in patients over 40 years of age.The prognosis is appalling. Indeed only 15 of 368 cases (4%) from a number of historical series have survived more than 5 years. Our results are similarly disappointing with no survivors at 5 years despite modern methods of management of bone tumours.While there is no difference in local recurrence rates or survival between limb reconstruction and limb ablation the poor prognosis for both means that neither can be recommended at present. Sarcomatous change in Pagetoid bone should therefore be regarded as a different disease to primary osteosarcoma. It remains an incurable disease with a poor prognosis.