Mohamad Farid

JAK-STAT and G-protein-coupled receptor signaling pathways are frequently altered in epitheliotropic intestinal T-cell lymphoma

Epitheliotropic intestinal T-cell lymphoma (EITL, also known as type II enteropathy-associated T-cell lymphoma) is an aggressive intestinal disease with poor prognosis and its molecular alterations have not been comprehensively characterized. We aimed to identify actionable easy-to-screen alterations that would allow better diagnostics and/or treatment of this deadly disease. By performing whole-exome sequencing of four EITL tumor-normal pairs, followed by amplicon deep sequencing of 42 tumor samples, frequent alterations of the JAK-STAT and G-protein-coupled receptor (GPCR) signaling pathways were discovered in a large portion of samples. Specifically, STAT5B was mutated in a remarkable 63% of cases, JAK3 in 35% and GNAI2 in 24%, with the majority occurring at known activating hotspots in key functional domains. Moreover, STAT5B locus carried copy-neutral loss of heterozygosity resulting in the duplication of the mutant copy, suggesting the importance of mutant STAT5B dosage for the development of EITL. Dysregulation of the JAK-STAT and GPCR pathways was also supported by gene expression profiling and further verified in patient tumor samples. In vitro overexpression of GNAI2 mutants led to the upregulation of pERK1/2, a member of MEK-ERK pathway. Notably, inhibitors of both JAK-STAT and MEK-ERK pathways effectively reduced viability of patient-derived primary EITL cells, indicating potential therapeutic strategies for this neoplasm with no effective treatment currently available.

The influence of primary site on outcomes in leiomyosarcoma: a review of clinicopathologic differences between uterine and extrauterine disease.

Background: Leiomyosarcomas (LMS) comprise 25% of soft tissue sarcomas. Recent reports suggest differences in treatment outcomes between uterine (uLMS) and extrauterine (eLMS) disease that may reflect distinct disease biologies. We sought to identify prognostic factors in LMS and clinicopathologic differences between uLMS and eLMS. Methods: This is a single-center retrospective study evaluating 97 eligible patients treated for LMS between 2002 and 2010. Results: Median follow-up was 21.2 months. uLMS affected 53% of patients, and was less common beyond age 60 years compared with eLMS (10% vs. 37%, P=0.002). Seventy-two percent of patients presented with nonmetastatic disease. Of these, 94% underwent curative surgery, among whom more uLMS patients achieved negative surgical margins (90% vs. 45%, P=0.003). There were no significant differences in adjuvant therapy use and relapse patterns between uLMS and eLMS. Half of metastatic patients received palliative chemotherapy, among whom 76% received anthracycline-based chemotherapy in first line to which response rate was 31%. Median overall survival was 45.2 months, 49.8 months in uLMS, and 40.5 months in eLMS (P=0.294). Among patients without metastases, median survival was 60.8 months (77.3 vs. 48.1 mo in uLMS and eLMS, respectively, P=0.194). In metastatic disease, median survival was 20.7 months (22.0 vs. 17.5 mo in uLMS and eLMS, respectively, P=0.936). Advanced disease stage, bone metastases and lack of metastasectomy prognosticated for inferior survival. Conclusions: While demonstrating interesting clinicopathologic differences, the evidence for uLMS and eLMS being biologically distinct remains inconclusive. Disease stage is prognostically most important in LMS.

Cutaneous versus Non-Cutaneous Angiosarcoma: Clinicopathologic Features and Treatment Outcomes in 60 Patients at a Single Asian Cancer Centre

Background: Angiosarcoma (AS) is an uncommon soft tissue sarcoma with dismal prognosis that presents either cutaneously (C-AS) or non-cutaneously (NC-AS). We compared the clinical features and treatment outcomes between these 2 groups. Methods: A single-centre study evaluating 60 AS patients between 2002 and 2012 was performed. Results: The median age was 70 years. C-AS of the scalp or face comprised 66% of patients. C-AS patients were older than NC-AS (median age 74 vs. 56 years; p < 0.001). Proportionately more C-AS patients presented with non-metastatic disease (86 vs. 50%; p = 0.007). Amongst resected C-AS and NC-AS patients, rates of positive surgical margins (53 vs. 50%; p = 1.00) and adjuvant therapy (25 vs. 43%; p = 0.626) were not significantly different, though proportionately fewer C-AS patients relapsed (36 vs. 78%; p = 0.038). Paclitaxel was the most common agent in first line palliative systemic therapy, achieving an objective response rate of 56%. Median overall survival was 11.2 months, with no significant difference between C-AS and NC-AS (11.3 vs. 9.8 months; p = 0.895). Conclusion: Distinct from AS in the West, our series demonstrates a clear preponderance of scalp AS. Disparities in clinical characteristics between C-AS and NC-AS did not translate into survival differences.

A promising new regimen for the treatment of advanced extranodal NK/T cell lymphoma

Extranodal NK/T cell lymphoma (ENKTL) is a distinct entity in the World Health Organization (WHO) classifi cation that is almost always associated with Epstein-Barr virus (EBV) infection and is more common among Asians. Although local radiotherapy is fairly effective in controlling early stage ENKTL, prognosis is dismal for patients with advanced stage ENKTL [1]. Currently, there is no standard fi rst line therapy for the treatment of advanced ENKTL. Anthracyclinebased regimens such as CHOP (cyclophosphamide, doxorubicin, vinciristine and prednisolone) yield dismal response rates ( 15%), partly because the neoplastic NK cells over-express p-glycoprotein, a mediator of the multidrug resistance (MDR) phenotype [2]. Other novel regimens incorporating L-asparaginase have reported better results [3] but await further confi rmation. We present a 30-year-old lady with advanced ENKTL who achieved complete response with a novel treatment regimen after progressing through L-asparaginase based chemotherapy. Our patient presented with a fi ve month history of fever, left eye redness and neck swelling. Computed tomography (CT) revealed generalized lymphadenopathy involving cervical, axillary, paratracheal, para-aortic, iliac and inguinal nodes as well as massive hepatosplenomegaly with splenic infarcts. Magnetic resonance imaging (MRI) brain/orbits showed no intracranial disease. The EBV DNA titre at diagnosis was 11 297 copies/ml. Biopsies taken from the nasopharyngeal soft tissue mass and the left submandibular lymph node revealed a neoplastic lymphoid population that expressed the pan-T cell markers CD2 and CD3, the NK cell marker CD56 and the cytotoxic molecule TIA1, with in situ hybridization for EBV encoded RNA (EBER) strongly positive. Bone marrow trephine biopsy revealed similar histological fi ndings. The patient thus had Stage IV nasal ENKTL, with an international prognostic index (IPI) score of 3 (elevated lactate dehydrogenase, advanced Ann Arbor Stage and multiple extranodal disease sites). She was started on an L-aspariginase based regimen that comprised dexamethasone, methotrexate, ifosfamide, L-asparaginase and etoposide (SMILE), a combination that had previously shown promising results in Phase I studies for patients with advanced or refractory ENKTL [2]. The chemotherapy was given over 14 days with growth factor support, and repeated every 28 days. Disease response was evaluated clinically, radiologically with positron emission tomography (PET)-CT, and with serial EBV DNA titres. Despite initial response, there was disease progression following cycle 3 of SMILE, with rising EBV DNA titres. Her treatment was also complicated by methotrexate retention and prolonged neutropenia. Treatment was then switched to a novel regimen comprising bortezomib, gemcitabine, ifosfamide and oxalipaltin (B-GIFOX) given over four days with growth factor support, repeated every two weeks. PET CT after two cycles revealed near complete response, with EBV titres rendered undetectable for two consecutive readings (see Figure 1). The chemotherapy was well tolerated with no signifi cant hematologic or extra-hematologic toxicities. The patient received a total of four cycles of chemotherapy with a progression free survival of two months.

Germline Mutations in Cancer Predisposition Genes are Frequent in Sporadic Sarcomas.

Associations of sarcoma with inherited cancer syndromes implicate genetic predisposition in sarcoma development. However, due to the apparently sporadic nature of sarcomas, little attention has been paid to the role genetic susceptibility in sporadic sarcoma. To address this, we performed targeted-genomic sequencing to investigate the prevalence of germline mutations in known cancer-associated genes within an Asian cohort of sporadic sarcoma patients younger than 50 years old. We observed 13.6% (n = 9) amongst 66 patients harbour at least one predicted pathogenic germline mutation in 10 cancer-associated genes including ATM, BRCA2, ERCC4, FANCC, FANCE, FANCI, MSH6, POLE, SDHA and TP53. The most frequently affected genes are involved in the DNA damage repair pathway, with a germline mutation prevalence of 10.6%. Our findings suggests that genetic predisposition plays a larger role than expected in our Asian cohort of sporadic sarcoma, therefore clinicians should be aware of the possibility that young sarcoma patients may be carriers of inherited mutations in cancer genes and should be considered for genetic testing, regardless of family history. The prevalence of germline mutations in DNA damage repair genes imply that therapeutic strategies exploiting the vulnerabilities resulting from impaired DNA repair may be promising areas for translational research.

Germline hemizygous deletion of CDKN2A–CDKN2B locus in a patient presenting with Li–Fraumeni syndrome

Li–Fraumeni syndrome (LFS) is a rare cancer predisposition syndrome usually associated with TP53 germline alterations. Its genetic basis in TP53 wild-type pedigrees is less understood. Using whole-genome sequencing, we identified a germline hemizygous deletion ablating CDKN2A–CDKN2B in a TP53 wild-type patient presenting with high-grade sarcoma, laryngeal squamous cell carcinoma and a family history suggestive of LFS. Patient-derived cells demonstrated reduced basal gene and protein expression of the CDKN2A-encoded tumour suppressors p14ARF and p16INK4A with concomitant decrease in p21 and faster cell proliferation, implying potential deregulation of p53-mediated cell cycle control. Review of 13 additional patients with pathogenic CDKN2A variants suggested associations of germline CDKN2A mutations with an expanded spectrum of non-melanoma familial cancers. To our knowledge, this is the first report of a germline gross deletion of the CDKN2A–CDKN2B locus in an LFS family. These findings highlight the potential contribution of germline CDKN2A deletions to cancer predisposition and the importance of interrogating the full extent of CDKN2A locus in clinical testing gene panels.

Brain metastasis in sarcoma: Does metastasectomy or aggressive multi-disciplinary treatment improve survival outcomes.

Brain metastasis is rare in sarcoma. Prognostic factors, optimal management strategies and therapeutic outcomes of such patients are not well studied. We aimed to evaluate the incidence, clinical characteristics and treatment outcomes of parenchymal brain metastasis in sarcoma patients.

A Pilot Study to Evaluate the Role of Therapeutic Drug Monitoring of Pegfilgrastim in Lymphoma Patients Receiving Chemotherapy

Background: Despite primary prophylaxis of febrile neutropenia (FN) with pegfilgrastim, studies have demonstrated a significant number of breakthrough FN events among Asian lymphoma patients receiving chemotherapy. This study was designed to investigate the association of pegfilgrastim concentrations during the lowest point of absolute neutrophil count (ANC nadir) after chemotherapy administration and the occurrence of breakthrough FN, to evaluate whether Therapeutic drug monitoring of pegfilgrastim can guide management of FN. Methods: This was a single-centre, prospective cohort study of Asian lymphoma patients who received prophylactic pegfilgrastim after completion of their chemotherapy. Pegfilgrastim serum concentrations were measured from blood samples taken during ANC nadir and at development of breakthrough FN using an enzyme-linked immunosorbent assay. Descriptive statistics, t-tests and correlation curves were used in the statistical analyses. Results: Nineteen patients were recruited from May to August 2012 and received 21 cycles of pegfilgrastim. Three (15.8%) developed breakthrough FN. The median pegfilgrastim concentration among patients who developed breakthrough FN was 0.257 (0.231–0.631) ng/ml, compared to 0.299 (0.001–0.829) ng/ml in patients who did not (p=0.740). Baseline ANC levels were significantly lower in patients with breakthrough FN (3.59 × 109/L, range 2.71–3.87) versus those who did not (5.36 × 109/L, range 2.80–16.48; p=0.014). Conclusion: There was no difference in pegfilgrastim levels during ANC nadir between patients who developed breakthrough FN and those who did not, but the study was underpowered. Therapeutic drug monitoring of pegfilgrastim cannot be recommended at this time.

Management of hepatitis B reactivation in lymphoma patients on rituximab with past hepatitis B exposure: An observational study

Background Currently, a standardized approach to prevent and manage hepatitis B reactivation in lymphoma patients with past hepatitis exposure receiving rituximab in Singapore is lacking. This study is designed to report the current management approach and outcomes associated with hepatitis B reactivation. Objectives The primary objective was to report 6-, 12-, 24-month cumulative hepatitis B reactivation-related outcomes. Secondary objectives were to report monitoring frequencies of hepatitis B DNA and liver function tests performed in lymphoma patients with resolved hepatitis B receiving rituximab, and anti-viral prophylaxis use. Methodology This was a single centre, retrospective observational study. Patients with resolved hepatitis B initiated on rituximab from January 2011 to December 2015 were identified and reviewed over a two-year period starting from the date of rituximab initiation. Relevant parameters were obtained from electronic medical records. Hepatitis B reactivation was defined by hepatitis B DNA levels 20 IU/ml (1.30 log/ml) and above. Data were analysed using descriptive statistics. Results Seventy-five patients were retrospectively reviewed over a two-year period. Hepatitis B reactivation was defined as hepatitis B DNA levels ≥20 IU/ml (1.30 log/ml). The 24-month cumulative hepatitis B reactivation rate was 4.0%. The median (interquartile range) number of hepatitis B DNA tests performed during treatment, initial six-month follow-up, and subsequent follow-up were 1.0 (0.0–2.6), 1.0 (0.0–2.0), and 1.0 (0.0–3.1), respectively. Conclusion Large variations in hepatitis B reactivation monitoring and management strategies were observed. Further studies are required to develop and determine a standardised protocol that could contribute to safer and more cost-effective care for lymphoma patients with resolved hepatitis B on rituximab.

Treatment and outcomes of melanoma in Asia: Results from the National Cancer Centre Singapore.

Acral melanoma (AM) and mucosal melanoma (MM) make up more than half of melanomas in Asia but comprise only 5% of cases in Caucasians, where cutaneous melanoma (CM) predominates. AM and MM are thought to be genetically and biologically distinct from CM. We report the characteristics and outcomes of melanoma patients from the National Cancer Centre Singapore.