Bruno Jim Rocca

Distinct Viral and Mutational Spectrum of Endemic Burkitt Lymphoma

Endemic Burkitt lymphoma (eBL) is primarily found in children in equatorial regions and represents the first historical example of a virus-associated human malignancy. Although Epstein-Barr virus (EBV) infection and MYC translocations are hallmarks of the disease, it is unclear whether other factors may contribute to its development. We performed RNA-Seq on 20 eBL cases from Uganda and showed that the mutational and viral landscape of eBL is more complex than previously reported. First, we found the presence of other herpesviridae family members in 8 cases (40%), in particular human herpesvirus 5 and human herpesvirus 8 and confirmed their presence by immunohistochemistry in the adjacent non-neoplastic tissue. Second, we identified a distinct latency program in EBV involving lytic genes in association with TCF3 activity. Third, by comparing the eBL mutational landscape with published data on sporadic Burkitt lymphoma (sBL), we detected lower frequencies of mutations in MYC, ID3, TCF3 and TP53, and a higher frequency of mutation in ARID1A in eBL samples. Recurrent mutations in two genes not previously associated with eBL were identified in 20% of tumors: RHOA and cyclin F (CCNF). We also observed that polyviral samples showed lower numbers of somatic mutations in common altered genes in comparison to sBL specimens, suggesting dual mechanisms of transformation, mutation versus virus driven in sBL and eBL respectively.

Notch3 is activated by chronic hypoxia and contributes to the progression of human prostate cancer

Prostate cancer (PC) is still the second cause of cancer‐related death among men. Although patients with metastatic presentation have an ominous outcome, the vast majority of PCs are diagnosed at an early stage. Nonetheless, even among patients with clinically localized disease the outcome may vary considerably. Other than androgen sensitivity, little is known about which other signaling pathways are deranged in aggressive, localized cancers. The elucidation of such pathways may help to develop innovative therapies aimed at specific molecular targets. We report that in a hormone‐sensitive PC cell line, LNCaP, Notch3 was activated by hypoxia and sustained cell proliferation and colony formation in soft agar. Hypoxia also modulated cellular cholesterol content and the number and size of lipid rafts, causing a coalescence of small rafts into bigger clusters; under this experimental condition, Notch3 migrated from the non‐raft into the raft compartment where it colocalized with the γ‐secretase complex. We also looked at human PC biopsies and found that expression of Notch3 positively correlated with Gleason score and with expression of carbonic anhydrase IX, a marker of hypoxia. In conclusion, hypoxia triggers the activation of Notch3, which, in turn, sustains proliferation of PC cells. Notch3 pathway represents a promising target for adjuvant therapy in patients with PC.

The alteration of lipid metabolism in Burkitt lymphoma identifies a novel marker: adipophilin.

Background Recent evidence suggests that lipid pathway is altered in many human tumours. In Burkitt lymphoma this is reflected by the presence of lipid droplets which are visible in the cytoplasm of neoplastic cells in cytological preparations. These vacuoles are not identifiable in biopsy section as lipids are “lost” during tissue processing. Methods and Results In this study we investigated the expression of genes involved in lipid metabolism, at both RNA and protein level in Burkitt lymphoma and in other B-cell aggressive lymphoma cases. Gene expression profile indicated a significant over-expression of the adipophilin gene and marked up-regulation of other genes involved in lipid metabolism in Burkitt lymphoma. These findings were confirmed by immunohistochemistry on a series od additional histological samples: 45 out of 47 BL cases showed strong adipophilin expression, while only 3 cases of the 33 of the not-Burkitt lymphoma category showed weak adipophilin expression (p<0.05). Conclusions Our preliminary results suggest that lipid metabolism is altered in BL, and this leads to the accumulation of lipid vacuoles. These vacuoles may be specifically recognized by a monoclonal antibody against adipophilin, which may therefore be a useful marker for Burkitt lymphoma because of its peculiar expression pattern. Moreover this peptide might represent an interesting candidate for interventional strategies.

Plasmablastic transformation of a pre-existing plasmacytoma: a possible role for reactivation of Epstein Barr virus infection

Background: Juvenile myelomonocytic leukemia (JMML) is an aggressive clonal myeloid neoplasm of early childhood associated with mutations in Ras pathway genes (PTPN11, KRAS, NRAS, CBL and NF1). Elevated fetal hemoglobin (HbF) levels and monosomy 7 are frequently observed. Stem cell transplantation is the only available curative treatment option but only provides an event-free survival of about 50%. Aims: Gain insight in the molecular networks involved in JMML pathogenesis based on mRNA, microRNA and long non-coding RNA transcriptome analysis of JMML samples. Methods: Expression of 27958 mRNA probes and 23042 lncRNA probes was assessed in diagnostic bone marrow or peripheral blood mononuclear cells of 63 JMML patients and 5 healthy donors, using a custom designed Agilent array. In addition, cDNA of 768 microRNAs was pre-amplified and quantified using miRNA specific Taqman probes. Results: Unsupervised clustering of an initial cohort of 14 patients generated two subgroups with let-7e and RNA-binding protein LIN28B amongst the most significantly differentially expressed genes. In the final cohort, relative higher LIN28B expression was observed in 35 of 63 cases (55.6%) and was defined as the average of the healthy donors plus three standard deviations. Univariable Cox regression showed that logarithmic LIN28B expression as a dichotomous variable can predict overall survival (p=0.035, exp(B) = 4.227, CI(95%) = 1.108 – 16.125). Patients with higher LIN28B mRNA levels experience a significant worse overall survival (Kaplan-Meier plot, p=0.022). HbF and platelet count were also significant prognostic factors, as described previously (p=0.023 and 0.027 respectively). There was no association between LIN28B expression and Ras pathway mutation status. We observed the strongest miRNA anti-correlation between LIN28B and five let-7 family members (d, b, g, e and a), and the second highest positive mRNA correlation between LIN28B and HMGA2. Recently, it was shown that the LIN28B – let-7 – HMGA2 axis determines higher self-renewal of fetal hematopoietic stem cells (Copley, 2013). This indicates that LIN28B confers augmented self- renewal to leukemic hematopoietic stem cells in JMML and – since this is an early childhood disease – this is potentially already initiated during embryogenesis. JMML patients frequently show elevated HbF levels at diagnosis. A positive correlation was found between LIN28B expression and HbF levels (rs=0.64, p<0.001, N = 41). Interestingly, our gene expression profiling data showed that both probes corresponding to HBG1 (encoding the human gamma globin chain) and HBBP1 (encoding a lncRNA-affiliated hemoglobin beta pseudogene) were strongly correlated with LIN28B expression in our patient series. This emphasizes the central role for LIN28B in the fetal (leukemic) hematopoietic stem cell system. Strikingly, patients with monosomy 7 (n=7/56) never displayed increased LIN28B expression (Chi-square p = 0.0017), suggesting the presence of a LIN28B activating transcription factor on chromosome 7. We identified MNX1 (HLXB9) as a possible activator of LIN28B based on a very strong correlation and siRNA knockdown.

Burkitt lymphoma beyond MYC translocation: N-MYC and DNA methyltransferases dysregulation.

BackgroundThe oncogenic transcription factor MYC is pathologically activated in many human malignancies. A paradigm for MYC dysregulation is offered by Burkitt lymphoma, where chromosomal translocations leading to Immunoglobulin gene-MYC fusion are the crucial initiating oncogenic events. However, Burkitt lymphoma cases with no detectable MYC rearrangement but maintaining MYC expression have been identified and alternative mechanisms can be involved in MYC dysregulation in these cases.MethodsWe studied the microRNA profile of MYC translocation-positive and MYC translocation-negative Burkitt lymphoma cases in order to uncover possible differences at the molecular level. Data was validated at the mRNA and protein level by quantitative Real-Time polymerase chain reaction and immunohistochemistry, respectively.ResultsWe identified four microRNAs differentially expressed between the two groups. The impact of these microRNAs on the expression of selected genes was then investigated. Interestingly, in MYC translocation-negative cases we found over-expression of DNA-methyl transferase family members, consistent to hypo-expression of the hsa-miR-29 family. This finding suggests an alternative way for the activation of lymphomagenesis in these cases, based on global changes in methylation landscape, aberrant DNA hypermethylation, lack of epigenetic control on transcription of targeted genes, and increase of genomic instability. In addition, we observed an over-expression of another MYC family gene member, MYCN that may therefore represent a cooperating mechanism of MYC in driving the malignant transformation in those cases lacking an identifiable MYC translocation but expressing the gene at the mRNA and protein levels.ConclusionsCollectively, our results showed that MYC translocation-positive and MYC translocation-negative Burkitt lymphoma cases are slightly different in terms of microRNA and gene expression. MYC translocation-negative Burkitt lymphoma, similarly to other aggressive B-cell non Hodgkin’s lymphomas, may represent a model to understand the intricate molecular pathway responsible for MYC dysregulation in cancer.

Benign glomus tumor of the urinary bladder.

Glomus tumors are rare, mesenchymal neoplasms of adulthood, which occur in both the sexes with equal frequency. Most of these tumors are benign, but some cases with atypical/malignant behavior have been reported. They most often occur in the extremities, typically in the subungual region of the fingers, and rarely involve the internal organs. We report the case of a 63-year-old man who presented with hematuria. The cystoscopy showed a polypoid lesion of the anterior wall of the bladder, which was diagnosed on biopsy as a benign glomus tumor. To the best of our knowledge, this is the first case of benign glomus tumor of the bladder described in the literature. This report widens the spectrum of the differential diagnoses of bladder neoplasms.

Renal infarction due to polyarteritis nodosa in a patient with angioimmunoblastic T-cell lymphoma: a case report and a brief review of the literature

Angioimmunoblastic T-cell lymphoma is one of the most common subtypes of peripheral T-cell lymphoma (15-20% of all cases), accounting for approximately 1-2% of all non-Hodgkin lymphomas. It often presents autoimmune phenomena including hemolytic anemia, thrombocytopenia, glomerulonephrities and circulating immune complexes. Polyarteritis nodosa is an autoimmune disease characterized by necrotizing vasculitis of medium vessels, which rarely develops in association with hematological malignant disorders. Herein we report the case of a 40-year-old man who underwent lymph node biopsy in the suspicious of sarcoidosis. On the basis of histological and immunohistochemical findings, the diagnosis of angioimmunoblastic T-cell lymphoma was performed. The patient was successfully treated with cytarabine-based regimen for 6 cycles. Three months after the initial diagnosis of angioimmunoblastic T-cell lymphoma, a whole body computed tomography showed a lesion in the lower pole of the left kidney. Renal cell carcinoma was suspected, thus a nephrectomy was carried out. The histological findings were compatible with polyarteritis nodosa. To the best of our knowledge, the association between polyarteritis nodosa and angioimmunoblastic T-cell lymphoma has been described only once. This relation may be secondary to the induction of an autoimmune phenomenon by the lymphoma with the formation of circulating immune complexes, leading to vessels walls injury. A careful evaluation is needed in the management of angioimmunoblastic T-cell lymphoma patients with signs of renal failure in order to avoid delay of treatment and organ damage.

Carbonic anhydrase IX is a marker of hypoxia and correlates with higher Gleason scores and ISUP grading in prostate cancer

BackgroundCarbonic anhydrase IX is a member of α-carbonic anhydrases that is preferentially expressed in solid tumors. It enables bicarbonate transport across the plasma membrane, neutralizing intracellular pH and conferring to cancer cells a survival advantage in hypoxic/acidic microenvironments. Overexpression of carbonic anhydrase IX in cancer tissues is regulated by hypoxia inducible factor 1α − mediated transcription and the enzyme is considered a marker of tumor hypoxia and poor outcome. The role of carbonic anhydrase IX in prostate cancer has not been fully clarified and controversy has arisen on whether this enzyme is overexpressed in hypoxic prostate cancer tissues.MethodsWe analyzed the expression of carbonic anhydrase IX and hypoxia inducible factor 1α in two prostate cancer cell lines, LNCaP and PC-3, and in 110 cancer biopsies, by western blotting and immunocyto/histochemistry.ResultsIn LNCaP and PC-3 cells, carbonic anhydrase IX was mostly cytoplasmic/nuclear, with very limited membrane localization. Nuclear staining became stronger under hypoxia. When we analyzed carbonic anhydrase IX expression in human prostate cancer biopsies, we found that protein staining positively correlated with hypoxia inducible factor 1α and with Gleason pattern and score, as well as with the novel grading system proposed by the International Society of Urological Pathology for prostate cancer. Once more, carbonic anhydrase IX was mainly cytoplasmic in low grade carcinomas, whereas in high grade tumors was strongly expressed in the nucleus of the neoplastic cell. An association between carbonic anhydrase IX expression level and the main clinic-pathological features involved in prostate cancer aggressiveness was identified.ConclusionsThere was a statistically significant association between carbonic anhydrase IX and hypoxia inducible factor 1α in prostate cancer tissues, that identifies the enzyme as a reliable marker of tumor hypoxia. In addition, carbonic anhydrase IX expression positively correlated with prostate cancer grading and staging, and with outcome, suggesting that the protein may be an independent prognosticator for the disease. The nuclear translocation of the enzyme in hypoxic cancer cells may epitomize a biological switch of the tumor towards a less favorable phenotype.

Primary anorectal Hodgkin lymphoma: report of a case and review of the literature

Primary colorectal lymphomas are very rare. They are mostly B-cell non-Hodgkin lymphomas. Only 2 cases of anorectal Hodgkin lymphoma have been described so far, both affecting HIV-infected males and showing Epstein-Barr virus infection. We report an unusual case of primary Hodgkin lymphoma of the anorectal region in an HIV-negative, Epstein-Barr virus-infected patient and in the absence of inflammatory bowel disease. The importance of distinguishing Hodgkin lymphoma from Epstein-Barr virus-induced lymphoproliferative disorders and from Epstein-Barr virus-positive diffuse large B-cell lymphoma of the elderly is stressed in particular in non-immunocompromised patients and in the absence of history of inflammatory bowel disease.

Lymphoepithelioma-Like Carcinoma of the Ovary

Only one case of lymphoepithelioma-like carcinoma of the ovary has been reported so far. A new case is herein illustrated in a 69-year-old woman: an ovarian mass adherent to urinary bladder dome with peritoneal carcinomatosis. Histologically, undifferentiated carcinomatous areas were intermingled with abundant lymphoid tissue. Epstein-Barr virus has not been detected either in neoplastic or in lymphoid cells.