Starting from human musculoskeletal sarcomas, we isolated a subset of cells that display cancer stem cell properties. The control of culture conditions is crucial to enhance the isolation of this cell population. Cancer stem cells (CSCs) have emerged as the real responsible for the development, chemoresistance, and metastatic spread of different human cancers, including musculoskeletal sarcomas. However, unlike most leukemias and solid tumors, so far, data on musculoskeletal sarcomas refer to CSCs obtained from established cell lines, and only a few authors have reported on the isolation of CSCs from tissue samples [1-7]. Reasonably due to some peculiar features of mesenchymal tumors, including the lack of unique surface markers that identify tumor progenitors, there are still partial clues on the existence of a CSC population in these cancers. Here, we report the identification of putative CSCs in musculoskeletal sarcomas using the most general accepted isolation method, the sphere culture system. Accordingly to recent reports, we also analyzed the effects of reduced oxygen availability on the behavior of sarcoma CSCs.Summary
Introduction
Solitary fibrous tumour (SFT) is a relatively uncommon mesenchymal neoplasm that most frequently arises in the pleura, but is also known to affect extrathoracic sites. About 15 % of SFT’s behave in an aggressive way, giving rise to local recurrence and/or distant metastasis. However, the behaviour of SFT remains unpredictable and due to the rarity of this tumour, it is difficult to define prognostic factors. The purpose of this study was to describe our experience with SFT, trying to define the pathologic features of this rare entity and better understand its clinical behaviour. We performed a clinicopathologic review of all cases treated for a SFT at the Istituto Ortopedico Rizzoli in Bologna, between 1996 and 2008. We included 24 patients, nine males and fifteen females, ranging in age from 22 to 82 years (median 43.5 years). The anatomical sites involved were: the thigh (12 cases), shoulder region (four cases), gluteus (three cases), foot (two cases), extrapleural thoracic wall (two cases), and the lower leg (one case). The tumour was >
5 cm in 15 cases, ranging in diameter from 2.5 cm to 18 cm (median 7.5 cm). Pain and swelling were the most frequently reported symptoms at presentation, with a mean duration of symptoms of 10 months. All patients were treated by excisional surgery (wide margins in 11, marginal margins in 13). Three patients had undergone pre-operative radiotherapy (44Gy) and one of these had also adjuvant radiotherapy after marginal excision of the tumour. Six tumours showed at least one atypical histologic feature (moderate to marked cytological atypia, extensive tumor necrosis, ≥ four mitoses per ten high-power fields, or infiltrative margins). On immunohistochemistry, 21 cases were positive for CD-34, 10 for CD-99, 17 for vimentin, three for CD-31, four for actin and one for S-100. Subsequent follow-up (average 33 months, range 5 to 112 months) revealed tumour relapse in only one case: a bone metastasis after 36 months of follow-up. The initial lesion was considered a large, deep, malignant SFT of the thigh, treated with wide surgical excision. In the current review, including 24 extrathoracic solitary fibrous tumours, all lesions but one had a benign course. Nevertheless, this entity has a potential to recur or metastasize, and therefore careful long-term follow-up is necessary for all patients, even after wide excisional surgery. Although specific prognostic factors are yet to be defined, a high degree of suspicion for malignant behaviour is warranted for those cases in which atypical histologic features are present, particularly in the context of a deep tumor >
5cm in diameter.
Forty-six hemangioendotheliomas (HE) of bone treated at Rizzoli from 1985 to 2004 were studied with minimum follow up of 4 years: 19 females and 27 males, mean age 37 years, mean follow-up 9 years, 35 cases unifocal at diagnosis (10 spine – 1 with lung metastasis also- 11 lower limb, 8 upper limb, 6 pelvis) and 11 with multifocal involvement. In 10 patients intralesional surgery was previously performed elsewhere. In 27 patients primarily treated at Rizzoli with unifocal localization, surgery was used in 15 cases, surgery and radiotherapy in 7, surgery with radio/chemotherapy in 1 and no surgery in 4 (2 radiotherapy, 1 radio/chemotherapy and 1 embolization). Eight unifocal patients already treated elsewhere had surgery in 3 cases, surgery and radiotherapy in 3, surgery with radio/chemotherapy in 1 and surgery plus chemotherapy in 1. Three of the unifocal cases had further bone involvement subsequently. Nine multifocal patients primarily treated at Rizzoli had surgery in 4 cases, surgery and radiotherapy in 4, surgery with radio/chemotherapy in 1. The 2 previously treated multifocal HE had 1 surgery and 1 radiotherapy. Six patients died: 3 of disease, 1 of radio-induced osteosarcoma, 2 of different disease. Two patients are AWD. Of remaining 40 patients, 26 are NED (mean follow up 9 years), 11 NED after treatment of recurrence, 1 NED after treatment of radio-induced sarcoma. No lung metastases were diagnosed after treatment. All 10 cases previously treated intralesionally had recurrence. Two of 15 unifocal cases treated with surgery recurred (13%). None of 9 resected unifocal cases previously untreated recurred. Two of 21 pts. with radiotherapy (9.5%) had radio-induced sarcoma. Surgery is recommended, resection when feasible. Radiotherapy, implying risk of induced sarcoma, should be reserved to multifocal or unresectable cases. Adverse prognostic factor was previous intralesional surgery.