MicroRNA profiling of multiple osteochondromas: identification of disease-specific and normal cartilage signatures.

Multiple osteochondroma (MO) is a rare skeletal disease characterized by the formation of multiple benign cartilage-capped bone tumors; in 1-5% of patients, a malignant transformation into peripheral chondrosarcoma may occur. This disorder is characterized by a large spectrum of germline mutations scattered along EXT1/EXT2 genes, the presence of a significant percentage of patients without alterations in EXT genes, and a large phenotypic variability. The molecular basis of MO genetic and clinical heterogeneity, including the causes underlying malignant transformation, is currently unknown. This leads to the lack of appropriate diagnostic/prognostic markers as well as of therapeutic options. Recently, specific microRNAs (miRNAs) were reported to be involved in chondrogenesis and inflammatory cartilage diseases. We therefore hypothesized a role for microRNAs in cartilaginous tumors and investigated microRNA expression in osteochondroma and normal cartilage tissues to evaluate whether they could affect osteochondromas onset and/or clinical manifestations. Our results indicate that miRNAs differentially expressed in MO samples may hamper the molecular signaling responsible for normal differentiation of chondrocytes, contributing to pathogenesis and clinical outcome. Although further studies are needed to validate our observations and to identify targets of miRNAs, this is the first study reporting on miRNA expression in growth plate and its comparison with pathological conditions.

Post-menopausal breast cancer risk: oral estrogen treatment and abdominal obesity induce opposite changes in possibly important biological variables.

Almost all of the epidemiological studies on the consequences of estrogen replacement treatment (ERT) refer to subjects treated with oral conjugated equine estrogens (CEE). These studies suggest that breast cancer (BC) risk is limited and can only be seen after long-term and/or high dosage use. Orally administered estrogens present a number of metabolic and endocrine peculiarities, some of which could be important in reducing the risk to the breast. Actually, these peculiarities are opposite to those observed in post-menopausal women with abdominal obesity (AO), a group which has recently been identified to be at high risk. AO (as other situations in which an increase in BC risk does exist) shows a sex-hormone-binding-globulin (SHBG) level reduction, which causes an increase of both estrogenic and androgenic activity. Further features of AO, possibly involved in BC risk, could be: i) increased free fatty acid (FFA) levels; ii) hyperinsulinemia; iii) increase of circulating insulin-like growth-factor-I (IGF-I) activity. On the contrary oral estrogens, through their hepatocellular effects, cause: i) a clearcut SHBG increase; ii) a trend to reduced circulating IGF-I activity. As a consequence, the possibility that oral estrogens are characterized by a favourable balance between estrogenic activity and biological modifications protective to the breast, is worth consideration. Even non-oral estradiol have a possible protective action through FFA level reduction; however, due to the absence of hepatocellular effect, it does not influence SHBG levels and IGF-I activity. It seems difficult to extend data on the relationship between BC and oral CEE to other types of types of ERT. For the latter, further study will be necessary.

[Pseudomyxoma of the peritoneum caused by rupture of a mucinous cystoma of the ovary. Description of a case]. / Pseudomixoma del peritoneo da rottura di cistoma mucinoso dell'ovaio. Descrizione di un caso.

A case of pseudomyxoma peritonei originating from spontaneous rupture of an ovaric mucinous cystoma is described: in this pathology we observe the spreading throughout the peritoneal cavity of free or encapsulated gelatinous masses arising from primitive lesion. The examined case presented a spreading of mucinous masses on contralateral ovary and omentum and a total laparo-hysterectomy, bilateral annessiectomy and omentectomy has been carried out. A year after surgery, on the base of a three months follow-up, no clinical or ultrasonic signs of local recurrence has been noticed. The pathogenesis of this pathology is discussed: the flogistic hypothesis considering such a spreading as a "foreign body" peritonitis and the neoplastic one, pointing out a metastatic process of mucus-secretive epithelia implantation as the etiopathogenetic moment of the injury, are actually the most accredited hypothesis by literature.

Genetic models of osteochondroma onset and neoplastic progression: evidence for mechanisms alternative to EXT genes inactivation.

Osteochondroma, the most common benign bone tumor, may occur as a sporadic lesion or as multiple neoplasms in the context of multiple osteochondromas syndrome. The most severe complication is malignant transformation into peripheral secondary chondrosarcoma. Although both benign conditions have been linked to defects in EXT1 or EXT2 genes, contradictory reports are present in the literature regarding the requirement of their biallelic inactivation for osteochondroma development. A major limitation of these studies is represented by the small number of samples available for the screening. Taking advantage of a large series of tissues, our aim was to contribute to the definition of a genetic model for osteochondromas onset and transformation. EXT genes point mutations and big deletions were analyzed in 64 tissue samples. A double hit was found in 5 out of 35 hereditary cases, 6 out of 16 chondrosarcomas and 2 recurrences; none of the 11 sporadic osteochondromas showed two somatic mutations. Our results clearly indicate that, in most cases, biallelic inactivation of EXT genes does not account for osteochondromas formation; this mechanism should be regarded as a common feature for hereditary osteochondromas transformation and as an event that occurs later in tumor progression of solitary cases. These findings suggest that mechanisms alternative to EXT genetic alteration likely have a role in osteochondromas pathogenesis.