Ubaldo Familiari

BCR-ABL disrupts PTEN nuclear-cytoplasmic shuttling through phosphorylation-dependent activation of HAUSP

Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by the t(9;22) translocation coding for the chimeric protein p210 BCR-ABL. The tumor suppressor phosphatase and tensin homolog (PTEN) has recently been shown to have a critical role in the pathogenesis of CML. Nuclear localization and proper nuclear-cytoplasmic shuttling are crucial for PTEN’s tumor suppressive function. In this study, we show that BCR-ABL enhances HAUSP-induced de-ubiquitination of PTEN in turn favoring its nuclear exclusion. We further demonstrate that BCR-ABL physically interacts with and phosphorylates HAUSP on tyrosine residues to trigger its activity. Importantly, we also find that PTEN delocalization induced by BCR-ABL does not occur in the leukemic stem cell compartment due to high levels of PML, a potent inhibitor of HAUSP activity toward PTEN. We therefore identify a new proto-oncogenic mechanism whereby BCR-ABL antagonizes the nuclear function of the PTEN tumor suppressor, with important therapeutic implications for the eradication of CML minimal residual disease.

HHV8-positive, HIV-negative multicentric Castleman’s disease: early and sustained complete remission with rituximab therapy without reactivation of Kaposi sarcoma

Multicentric Castleman’s disease (MCD) is a rare lymphoproliferative disorder with systemic symptoms and poor prognosis and is characterized by an abnormal proliferation of polyclonal plasmablasts in the mantle zone of B-cell follicles. The disease is found primarily in chronic HIV carriers and is usually strictly associated with human herpes virus type 8 (HHV-8) coinfection, which is believed to play a key role in the pathogenesis of MCD. The disease is also diagnosed in HIV-negative patients, who are usually elderly or immunosuppressed; however, in about half of these cases, no evidence of HHV8 infection is found. The anti-CD20 monoclonal antibody rituximab is now the preferred treatment for HIV-positive MCD. However, it is not clear whether rituximab is effective in HIV-negative patients with MCD, particularly in the HHV8-positive subset. We report here the clinical and biologic courses of two HIV-negative, HHV8-positive patients with MCD who were treated with rituximab. In both cases, a significant clinical improvement was observed after the first two infusions, which was shortly followed by a drop in HHV8 viremia to undetectable levels. Both patients underwent complete clinical remission, which persisted without relapse at 30 and 9 months of follow-up, respectively. No reactivation of the Kaposi sarcoma found in a lymph node of one of the patients was observed. Our report, along with additional data present in the literature, suggests that rituximab may be an appropriate and safe first-line therapy for HIV-negative, HHV8-positive MCD.

Thymic Basaloid Carcinoma: A Clinicopathologic Study of 12 Cases, With a General Discussion of Basaloid Carcinoma and Its Relationship With Adenoid Cystic Carcinoma

Thymic carcinoma (primary carcinoma of the thymic epithelium; type C thymoma) is a rare malignancy. It usually presents in middle-aged to elderly patients and can exhibit a wide variety of morphologic appearances. Thymic basaloid carcinoma (thymic BC) is a particularly rare subtype, with less than 20 cases published in the English literature, mostly in the form of individual case reports. In this study, we present the clinicopathologic and immunohistochemical features of 12 new cases of thymic BC. There were 10 (83%) men and 2 (17%) women. Ages at the time of initial diagnosis ranged from 34 to 77 years (mean 55 y). The 2 most common manners of presentation were dyspnea on exertion (3 patients) and as an incidental finding on radiographic imaging (2 patients). Tumors ranged in size from 4.4 to 17 cm (mean 10.1 cm). One of 12 cases (8.3%) was associated with a multilocular thymic cyst. Immunohistochemistry was performed in 8 cases. Pan-cytokeratin was positive in all cases. CD117 (c-kit) was positive in 6 of 8 cases (75%), p63 was positive in 7 of 8 cases (88%), p53 was positive in 7 of 8 cases (88%), ranging from <10% to 90%, CD5 was focally positive in 3 of 8 cases (38%), collagen type IV was positive in 4 of 8 cases (50%), and proliferative index, as estimated by Ki67, ranged from <1% to approximately 15%. In 1 of 2 cases with sarcomatoid differentiation, Ki67 was greater than 80% in the sarcomatoid area. Cases were negative for thyroid transcription factor-1 (0 of 8), S-100 (0 of 7), and synaptophysin (0 of 7). Long-term data was available in 8 patients with an average follow-up of 30 months. Five patients died of their disease at an average of 34 months from the time of diagnosis. Of the remaining 3 patients, 1 had a stable recurrence and died at 4 years from unrelated causes, and 2 were alive without the evidence of disease at 12 and 7 months, respectively. Thymic BC, although previously regarded as a low-grade neoplasm, has shown that it is capable of aggressive behavior and significant mortality. In this paper, we review the pertinent literature and discuss the possible relationship of thymic BC with thymic adenoid cystic carcinoma, as well as BCs and adenoid cystic carcinomas at other sites.

CT features of solitary fibrous tumour of the pleura: experience in 26 patients

Purpose.The purpose of this study was to identify the typical computed tomography (CT) features of solitary fibrous tumours of the pleura (SFTP) and determine which findings would allow confirmation of the pleural origin or benign behaviour of the tumour.Materials and methods.Twenty–six preoperative CT studies of the chest (23 enhanced and 14 unenhanced) were retrospectively reviewed.Results.Up to 50% of SFTP were larger than 10 cm. At unenhanced CT, they showed homogeneous attenuation in 5 cases (35.7%) and inhomogeneous attenuation in 9 (64.3%). At contrastenhanced CT, they were inhomogeneous in 21 cases (91.3%), with geographic pattern (61.9% of cases), serpiginous linear areas of enhancement (intralesional vessels) (23.8%), rounded (52.4%) or linear (33.3%) areas of low attenuation (necrosis).Conclusions.Depending on location, size and histological features, SFTP may produce a large spectrum of findings. Typical CT features of small SFTP were well–defined margins and smooth contours, homogeneous attenuation and right or obtuse angles with the pleura. Larger lesions were characterised by well–defined margins and lobulated contours, geographic pattern in enhanced CT scans, acute angles or smooth tapering margins with the pleura.

Morgana acts as an oncosuppressor in chronic myeloid leukemia

We recently described morgana as an essential protein able to regulate centrosome duplication and genomic stability, by inhibiting ROCK. Here we show that morgana (+/-) mice spontaneously develop a lethal myeloproliferative disease resembling human atypical chronic myeloid leukemia (aCML), preceded by ROCK hyperactivation, centrosome amplification, and cytogenetic abnormalities in the bone marrow (BM). Moreover, we found that morgana is underexpressed in the BM of patients affected by atypical CML, a disorder of poorly understood molecular basis, characterized by nonrecurrent cytogenetic abnormalities. Morgana is also underexpressed in the BM of a portion of patients affected by Philadelphia-positive CML (Ph(+) CML) caused by the BCR-ABL oncogene, and in this condition, morgana underexpression predicts a worse response to imatinib, the standard treatment for Ph(+) CML. Thus, morgana acts as an oncosuppressor with different modalities: (1) Morgana underexpression induces centrosome amplification and cytogenetic abnormalities, and (2) in Ph(+) CML, it synergizes with BCR-ABL signaling, reducing the efficacy of imatinib treatment. Importantly, ROCK inhibition in the BM of patients underexpressing morgana restored the efficacy of imatinib to induce apoptosis, suggesting that ROCK inhibitors, combined with imatinib treatment, can overcome suboptimal responses in patients in which morgana is underexpressed.

Fibrous tumour of the pleura (SFTP): a proteiform disease. Clinical, histological and atypical radiological patterns selected among our cases.

First described by Klemperer and Rabin in 1931, solitary fibrous tumour of the pleura (SFTP) is a mesenchymal tumour that tends to involve the pleura, although it has also been described in other thoracic areas (mediastinum, pericardium and pulmonary parenchyma) and in extrathoracic sites (meninges, epiglottis, salivary glands, thyroid, kidneys and breast). SFTP usually presents as a peripheral mass abutting the pleural surface, to which it is attached by a broad base or, more frequently, by a pedicle that allows it to be mobile within the pleural cavity. A precise preoperative diagnosis can be arrived at with a cutting-needle biopsy, although most cases are diagnosed with postoperative histology and immunohistochemical analysis of the dissected sample. SFTP, owing to its large size or unusual locations (paraspinal, paramediastinal, intrafissural and intraparenchymal), can pose interpretation problems or, indeed, point towards a diagnosis of diseases of a totally different nature. We present some unusual radiographic and computed tomography (CT) images of large SFTP or SFTP located in atypical thoracic locations in patients who underwent surgical resection.RiassuntoIl tumore fibroso solitario della pleura (TFSP), descritto per la prima volta da Klemperer e Rabin nel 1931, é una neoplasia mesenchimale che solitamente coinvolge la pleura, ma che viene descritta anche in altre sedi sia toraciche, quali il mediastino, il pericardio ed il parenchima polmonare, sia extratoraciche, quali le meningi, l’epiglottide, le ghiandole salivari, la tiroide, i reni e la mammella. Di solito si presenta come massa periferica a contatto con la superficie pleurica alla quale è unito da una larga base d’impianto o più spesso da un peduncolo che lo puè rendere mobile all’interno del cavo pleurico. La diagnosi preoperatoria di certezza puè essere ottenuta mediante biopsia con ago tranciante, ma nella maggior parte dei casi è post-chirurgica, frutto dell’esame istologico e dell’analisi immuno-istochimica sul pezzo operatorio. Il tumore fibroso solitario della pleura tuttavia, spesso a causa delle notevoli dimensioni o dello sviluppo in sedi inconsuete (paraspinali, paramediastiniche, intrascissurali ed intraparenchimali) può creare numerose difficoltà di interpretazione o addirittura orientare la diagnosi verso patologie di tutt’altra natura. In questo lavoro presentiamo gli aspetti radiologici inusuali di TFSP di grosse dimensioni o localizzati in sedi toraciche atipiche in pazienti sottoposti ad intervento chirurgico di exeresi.

Therapeutic inhibition of USP7-PTEN network in chronic lymphocytic leukemia: a strategy to overcome TP53 mutated/deleted clones

Chronic Lymphocytic Leukemia (CLL) is a lymphoproliferative disorder with either indolent or aggressive clinical course. Current treatment regiments have significantly improved the overall outcomes even if higher risk subgroups - those harboring TP53 mutations or deletions of the short arm of chromosome 17 (del17p) - remain highly challenging. In the present work, we identified USP7, a known de-ubiquitinase with multiple roles in cellular homeostasis, as a potential therapeutic target in CLL. We demonstrated that in primary CLL samples and in CLL cell lines USP7 is: i) over-expressed through a mechanism involving miR-338-3p and miR-181b deregulation; ii) functionally activated by Casein Kinase 2 (CK2), an upstream interactor known to be deregulated in CLL; iii) effectively targeted by the USP7 inhibitor P5091. Treatment of primary CLL samples and cell lines with P5091 induces cell growth arrest and apoptosis, through the restoration of PTEN nuclear pool, both in TP53-wild type and -null environment. Importantly, PTEN acts as the main tumor suppressive mediator along the USP7-PTEN axis in a p53 dispensable manner. In conclusion, we propose USP7 as a new druggable target in CLL.

Non genomic loss of function of tumor suppressors in CML: BCR-ABL promotes IκBα mediated p53 nuclear exclusion

Tumor suppressor function can be modulated by subtle variation of expression levels, proper cellular compartmentalization and post-translational modifications, such as phosphorylation, acetylation and sumoylation. The non-genomic loss of function of tumor suppressors offers a challenging therapeutic opportunity. The reactivation of a tumor suppressor could indeed promote selective apoptosis of cancer cells without affecting normal cells. The identification of mechanisms that affect tumor suppressor functions is therefore essential. In this work, we show that BCR-ABL promotes the accumulation of the NFKBIA gene product, IκBα, in the cytosol through physical interaction and stabilization of the protein. Furthermore, BCR-ABL/IκBα complex acts as a scaffold protein favoring p53 nuclear exclusion. We therefore identify a novel BCR-ABL/IκBα/p53 network, whereby BCR-ABL functionally inactivates a key tumor suppressor.

Fetal Adenocarcinoma of the Lung in a 25-Year-Old Woman

We report the case of a 25-year-old woman with a chance detection at x-ray of a well-defined mass in the right upper lobe during a medical examination. The patient suffered from a modest flu syndrome, with cough and fever. She was a current smoker. CT scan showed a homogeneous well-defined perihilar mass without calcifications, located in the right upper lobe and fully surrounded by aerated parenchyma. A right upper lobectomy with mediastinal lymph node sampling was performed. A pathologic diagnosis of well-differentiated fetal adenocarcinoma of the lung was made and staged as T2N0. Few cases of this type of malignancy have been reported in literature.

Messenger RNA and protein expression of thymidylate synthase and DNA repair genes in thymic tumors

BACKGROUND Thymic epithelial tumors include several entities with different biologic behavior. Chemotherapy is indicated in advanced disease, but limited data exist on gene expression correlation with the response to chemotherapeutic agents. PATIENTS AND METHODS A series of 69 thymic neoplasms (7 A-, 6 AB-, 6 B1-, 10 B2-, 14 B3-thymomas, 22 carcinomas and 4 combined tumors) was collected to assess gene expression of thymidylate synthase (TS), excision repair cross complementing-1 (ERCC1), ribonucleotide reductase subunit 1 (RRM1), topoisomerase 2α (TOP2A) and mTOR. RESULTS A strong linear correlation between TS gene and protein expression was observed (P<0.0001, R=0.40). TS expression was significantly lower in pure A-thymomas and thymic carcinomas (P<0.0001) and progressively decreasing from B1-type to thymic carcinomas (B1>B2>B3>C; P<0.0001). RRM1 and TOP2A mRNA expression levels were significantly correlated with TS levels (both P=0.03) with a similar trend of expression among histotypes. RRM1 and TOP2A high levels were significantly correlated with high TS (P=0.03) and low tumor stages (I-II) (P<0.0001 and P<0.01, respectively). No relevant changes of ERCC1 and mTOR were detected. CONCLUSIONS Low TS and, to a minor extent, RRM1 and TOP2A expression were detected in aggressive thymic tumors. These findings should be prospectively considered in selecting the most appropriate chemotherapy.