Maria Giulia Pirini

Analysis of all subunits, SDHA, SDHB, SDHC, SDHD, of the succinate dehydrogenase complex in KIT/PDGFRA wild-type GIST.

Mutations of genes encoding the subunits of the succinate dehydrogenase (SDH) complex were described in KIT/PDGFRA wild-type GIST separately in different reports. In this study, we simultaneously sequenced the genome of all subunits, SDHA, SDHB, SDHC, and SDHD in a larger series of KIT/PDGFRA wild-type GIST in order to evaluate the frequency of the mutations and explore their biological role. SDHA, SDHB, SDHC, and SDHD were sequenced on the available samples obtained from 34 KIT/PDGFRA wild-type GISTs. Of these, in 10 cases, both tumor and peripheral blood (PB) were available, in 19 cases only tumor, and in 5 cases only PB. Overall, 9 of the 34 patients with KIT/PDGFRA wild-type GIST carried mutations in one of the four subunits of the SDH complex (six patients in SDHA, two in SDHB, one in SDHC). WB and immunohistochemistry analysis showed that patients with KIT/PDGFRA wild-type GIST who harbored SDHA mutations exhibited a significant downregulation of both SDHA and SDHB protein expression, with respect to the other GIST lacking SDH mutations and to KIT/PDGFRA-mutated GIST. Clinically, four out of six patients with SDHA mutations presented with metastatic disease at diagnosis with a very slow, indolent course. Patients with KIT/PDGFRA wild-type GIST may harbor germline and/or de novo mutations of SDH complex with prevalence for mutations within SDHA, which is associated with a downregulation of SDHA and SDHB protein expression. The presence of germline mutations may suggest that these patients should be followed up for the risk of development of other cancers.

Molecular characterization of metastatic exon 11 mutant gastrointestinal stromal tumors (GIST) beyond KIT/PDGFRα genotype evaluated by next generation sequencing (NGS).

About 85% of GISTs are associated with KIT and PDGFRα gene mutations, which predict response to tyrosine kinase inhibitors. Although the outcomes in patients affected by GIST have dramatically improved, tumor progression control still remains a challenge. The aim of this study is the genomic characterization of individual metastatic KIT-exon 11-mutant GIST to identify additional aberrations and simultaneous molecular events representing potential therapeutic targets. Seven patients with metastatic GIST were studied with whole transcriptome sequencing and copy number analysis. Somatic single nucleotide variations were called; however, no shared mutated genes were detected except KIT. Almost all patients showed loss of genomic regions containing tumor suppressor genes, sometimes coupled with single nucleotide mutation of the other allele. Additionally, six fusion transcripts were found and three patients showed amplifications involving known oncogenes. Evaluating the concordance between CN status and mRNA expression levels, we detected overexpression of CCND2 and EGFR and silencing of CDKN2A, CDKN2C, SMARCB1, PTEN and DMD. Altered expression of these genes could be responsible for aberrant activation of signaling pathways that support tumor growth. In this work, we assessed the effect of Hedgehog pathway inhibition in GIST882 cells, which causes decrement of cell viability associated with reduction of KIT expression. Additional genomic alterations not previously reported in GIST were found even if not shared by all samples. This contributes to a more detailed molecular understanding of this disease, useful for identification of new targets and novel therapeutics and representing a possible point of departure for a truly individualized clinical approach.

Real-time quantitative assay for routine testing of HCV RNA in formalin-fixed, paraffin-embedded liver samples.

The assessment of hepatitis C virus (HCV) RNA in liver tissues is clinically relevant in cases where histology, liver function tests, and HCV serology are not sufficient for a definitive diagnosis of HCV-related hepatitis. We analyzed 215 formalin-fixed, paraffin-embedded liver needle biopsies from patients infected with HCV genotypes 1b and 2. HCV RNA extracted from paraffin sections were quantified by means of a TaqMan real-time reverse transcription-polymerase chain reaction method. The quantification of HCV RNA in liver tissue was correlated with the amount of HCV detected by immunohistochemistry (IHC) on paired frozen biopsies, the HCV RNA load in the serum, and the main serum tests of liver function and cholestasis. HCV RNA was detected by real-time reverse transcription-polymerase chain reaction in 169 liver biopsies (78.6%) with a mean value of 13.59±37.25 IU/ng. Tissue HCV RNA levels strongly correlated with the IHC results (P<0.001, Spearman test), HCV serum load (P<0.001), aspartate aminotransferase (P=0.001), γ-glutamyl transpeptidase (P=0.012), and aspartate aminotransferase/alanine aminotransferase ratio (P=0.029). HCV RNA was amplified in up to 7-year-old archival tissue samples. Real-time HCV RNA quantification on archival liver tissue may be clinically relevant in case of “occult” HCV infection or for the diagnosis of patients with known HCV infection and hepatic dysfunction but seronegative for HCV RNA. The assessment of the levels of HCV RNA in the liver might also be important for monitoring the effectiveness of antiviral therapy and the progression of disease in patients with chronic HCV hepatitis.

Surgical second-look in high risk gastrointestinal stromal tumor of small intestine: A case report

INTRODUCTION The peritoneum is one of the most common sites of distant gastrointestinal stromal tumor (GIST) metastases. In particular, GIST arising from the small intestine with resected minimal synchronous macroscopic peritoneal carcinomatosis or with primary tumor rupture has a higher risk of developing peritoneal recurrence. Current clinical practice does not envisage second-look surgery in GIST patients at high risk of developing peritoneal recurrence, and no literature data are available. PRESENTATION OF CASE We describe a 45-year-old woman who underwent emergency surgical resection of jejunal GIST presenting with spontaneous tumor rupture, synchronous ovarian and minimal macroscopic peritoneal involvement, and subsequent second-look surgery after 13 months of imatinib treatment. DISCUSSION Second-look surgery confirmed a 2.6cm lesion close to the mesenteric border of the fourth jejunal loop, and 11 peritoneal lesions with a macroscopic necrotic aspect related to treatment response. After conversion to an open procedure, a segmental jejunal resection was performed with removal of all peritoneal lesions and macroscopic radical cytoreduction. CONCLUSION Second-look surgery in selected GIST patients may be performed after at least 12 months of medical treatment with tyrosine-kinase inhibitors to identify those patients with limited peritoneal disease not disclosed by instrumental imaging who could undergo radical cytoreduction of peritoneal lesions.

Giant abdominal metastasis from cardiac liposarcoma

The patient was a 58-year-old man. His history began 6 years before the admission to our hospital because of a syncopal episode. MRI showed a 2 cm lesion at the confluence of the left pulmonary veins. It was surgically removed and the histopathological diagnosis was of ‘pleomorphic liposarcoma’. The postoperative course was regular. Since the patient lived in a rural area, he was not treated in a high-volume reference centre for sarcoma and follow-up was not managed by a dedicated multidisciplinary team. Three years later, for the onset of an intestinal occlusion, he underwent emergency laparotomy. An ileo-ileal invagination due to a little ileal lesion was treated with a 30 cm intestinal resection. The histopathological response was again of liposarcoma. Chemotherapy was not performed. One year later, a thoracoabdominal CT scan showed a heart recurrence and an enormous abdominal mass involving many ileal loops with intestinal subocclusion. The patient was evaluated in a reference centre for sarcoma and he was deemed inoperable. Because the symptomatology progressively worsened with continuous episodes of melena and severe anaemia, he showed up at our emergency department in extremely critical condition. Thoracoabdominal CT scan confirmed both abdominal and cardiac recurrences (figure 1). An emergency life-saving surgery …