Prognostic implication of the neoadjuvant rectal score and other biomarkers of clinical outcome in Hong Kong Chinese patients with locally advanced rectal cancer undergoing neoadjuvant chemoradiotherapy.

BACKGROUND: Neoadjuvant chemoradiotherapy is a standard treatment for locally advanced rectal cancer, for which pathological complete response is typically used as a surrogate survival endpoint. Neoadjuvant rectal score is a new biomarker that has been shown to correlate with survival. The main objectives of this study were to investigate factors contributing to pathological complete response, to validate the prognostic significance of neoadjuvant rectal score, and to investigate factors associated with a lower neoadjuvant rectal score in a cohort of Hong Kong Chinese. METHODS: Data of patients with locally advanced rectal cancer who received neoadjuvant chemoradiotherapy from August 2006 to October 2018 were retrieved from hospital records and retrospectively analysed. RESULTS: Of 193 patients who had optimal response to neoadjuvant chemoradiotherapy and surgery, tumour down-staging was the only independent prognostic factor that predicted pathological complete response (P<0.0001). Neoadjuvant rectal score was associated with overall survival (hazard ratio [HR]=1.042, 95% confidence interval [CI]=1.021-1.064; P<0.0001), disease-free survival (HR=1.042, 95% CI=1.022-1.062; P<0.0001), locoregional recurrence-free survival (HR=1.070, 95% CI=1.039-1.102; P<0.0001) and distant recurrence-free survival (HR=1.034, 95% CI=1.012-1.056; P=0.002). Patients who had pathological complete response were associated with a lower neoadjuvant rectal score (P<0.0001), but pathological complete response was not associated with survival. For patients with intermediate neoadjuvant rectal scores, late recurrences beyond 72 months from diagnosis were observed. CONCLUSION: Neoadjuvant rectal score is an independent prognostic marker of survival and disease recurrence in a cohort of Hong Kong Chinese patients who received neoadjuvant chemoradiotherapy for locally advanced rectal cancer.

PRAME immunostain expression in sebaceous lesions, cutaneous carcinomas and adnexal structures.

The use of immunostain for PRAME antigen is well established for cutaneous melanolocytic lesions. However, its staining in other cutaneous structures and lesions is under reported. This study assessed PRAME staining in a large cohort of normal skin tissue, sebaceous lesions, and cutaneous carcinomas to better delineate patterns of PRAME immunoreactivity. PRAME immunostaining was performed on sections of sebaceous lesions and tissue microarrays of basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs). Normal cutaneous adnexal structures were assessed on the sections of sebaceous lesions. For sebaceous lesions and non-lesional sebaceous glands, PRAME immunostaining was assessed for mature, germinative and sebocytes independently. A total of 193 sebaceous lesions, 64 BCCs and 35 SCCs were stained for PRAME immunostain. Staining pattern was predominantly cytoplasmic in normal apocrine glands, germinative sebocytes of sebaceous glands, and hair germs (p<0.001). Lesional sebocytes did not show different staining compared to normal sebaceous glands (p>0.05). Rare nuclear staining was observed in the normal epidermis (0.6%) and junctional melanocytes (4.1%). BCC, SCC and sebaceous carcinoma all showed low levels of PRAME immunoreactivity with variable proportions of cases demonstrating nuclear staining (BCC 59.4%, SCC 37.1%, sebaceous carcinoma 5.3%). PRAME immunostaining is positive in germinative sebocytes, various cutaneous structures and carcinomas. Nuclear staining, identical to melanoma, was observed in normal epidermis, junctional melanocytes, BCCs, SCCs, and sebaceous carcinomas. The pattern of PRAME staining in the skin must be recognised to avoid pitfalls in interpretating PRAME immunostain.

Spindle cell/sclerosing rhabdomyosarcoma with DCTN1::ALK fusion: broadening the molecular spectrum with potential therapeutic implications.

Spindle cell/sclerosing rbabdomyosarcoma (RMS) is a recently characterized variant of RMS with several distinct molecular subtypes. We describe an example occurring in the tongue of a 10-year-old boy with a novel DCTN1::ALK fusion. The tumor exhibited infiltrative growth and was comprised of fascicles and focally whorls of spindle cells with eosinophilic cytoplasm, in a collagenous or myxoid stroma. Moderate cytologic atypia, mitotic activity (2/10 HPFs), and perineural invasion were identified. The tumor cells expressed actin, desmin, MyoD1, myogenin, and ALK. An in-frame fusion between DCTN1 exon 26 and ALK exon 20 was detected by RNA sequencing, which was confirmed by split reads and supported by FISH studies. The tumor showed an indolent behavior with local recurrence 3 years after excision. This study broadens the molecular spectrum of spindle cell/sclerosing RMS and this molecular aberration may represent a potential therapeutic target for unresectable or disseminated disease.

Ocular PEComas are frequently melanotic and TFE3-translocated: report of two cases including the first description of PRCC-TFE3 fusion in PEComa.

Ocular perivascular epithelioid cell tumor (PEComa) is exceedingly rare. We reported two examples involving the choroid and subconjunctival tissue, respectively, in patients aged 17 and 20 years. Both tumors comprised packets and sheets of large polygonal cells with moderately pleomorphic nuclei and prominent nucleoli, traversed by delicate fibrovascular septa. Melanin pigmentation was present in one case. The tumors showed HMB45 and TFE3 immunoreactivity. TFE3 gene translocation was confirmed by FISH break-apart probes. RNA seq revealed PRCC-TFE3 and NONO-TFE3 fusions, with the former representing the first description of PRCC-TFE3 in PEComa. Critical reappraisal of the reported cases showed that ocular PEComa frequently affected young patents with melanin pigmentation, frequent TFE3 protein expression, and/or TFE3 gene translocation. No recurrence or metastasis was reported after complete excision despite the presence of cytologic atypia.

Oncogenes expand during evolution to withstand somatic amplification.

Background: Cancer-related genes are under intense evolutionary pressure. We conjectured that gene size is an important determinant of amplification propensity for oncogenes and thus cancer susceptibility and therefore could be subject to natural selection. Patients and methods: Gene information, including size and genomic locations, of all protein-coding genes were downloaded from Ensembl (release 87). Quantification of gene amplification was based on Genomic Identification of Significant Targets in Cancer scores obtained from available The Cancer Genome Atlas studies. Results: Oncogenes are larger in size as compared with non-cancer genes (mean size: 92.1 kb versus 61.4 kb; P < 0.0001) in the human genome, which is contributed by both increased total exon size (mean size: 4.6 kb versus 3.4 kb; P < 0.0001) and higher intronic content (mean %: 84.8 versus 78.0; P < 0.01). Such non-random size distribution and intronic composition are conserved in mouse and Drosophila (all P < 0.0001). Stratification by gene age indicated that young oncogenes have been subject to a stronger evolutionary pressure for gene expansion than their non-cancer counterparts. Pan-cancer analysis demonstrated that larger oncogenes were amplified to a lesser extent. Tumor-suppressor genes also moved toward small oncogenes in the course of evolution. Conclusions: Oncogenes expand in size whereas tumor-suppressor genes move closer to small oncogenes in the course of evolution to withstand oncogenic somatic amplification. Our findings have shed new light on the previously unappreciated influence of gene size on oncogene amplification and elucidated how cancers have shaped our genome to its present configuration.

TEAD1/4 exerts oncogenic role and is negatively regulated by miR-4269 in gastric tumorigenesis.

TEA domain (TEAD) transcription factors are key components of the Hippo-YAP1 signaling pathway, but their functional role and regulatory mechanisms remain unclear. This study aims to comprehensively explore the expression pattern and functional role of TEAD family in gastric carcinogenesis and investigate its regulation by microRNAs (miRNAs). The mRNA and protein expression of TEAD family were examined by quantitative reverse transcription-PCR (qRT-PCR) and western blot. Their functional roles were determined by in vitro and in vivo studies. The clinicopathological association of TEAD4 in gastric cancer (GC) was studied using immunohistochemistry on tissue microarray. The prediction of miRNAs, which potentially target TEAD1/4, was performed by TargetScan and miRDB. The regulation of TEAD1/4 by miRNAs was confirmed by qRT-PCR, western blot and luciferase assays. TEAD1/4 were overexpressed in GC cell lines and primary GC tissues. Knockdown of TEAD1/4 induced a significant anticancer effect in vitro and in vivo. TEAD1 was confirmed to be a direct target of miR-377-3p and miR-4269, while TEAD4 was negatively regulated by miR-1343-3p and miR-4269. Among them, miR-4269 was the most effective inhibitor of TEAD1/4. Ectopic expression of these miRNAs substantiated their tumor-suppressive effects. In primary GC tumors, downregulation of miR-4269 was associated with poor disease-specific survival and showed a negative correlation with TEAD4. TEAD1 and TEAD4 are oncogenic factors, whose aberrant activation are, in part, mediated by the silence of miR-377-3p, miR-1343-3p and miR-4269. For the first time, the nuclear accumulated TEAD4 and downregulated miR-4269 are proposed to serve as novel prognostic biomarkers in GC.

Clinical heterogeneity in children with gonadal dysgenesis associated with non-mosaic 46,XY karyotype.

INTRODUCTION: Gonadal dysgenesis is unique in disorders of sex development (DSD), in that it can be associated with 46,XX, 46,XY or mosaic 45,X/46,XY karyotypes. Gonadal dysgenesis can be partial or complete. Gonadal dysgenesis associated with the Y-chromosome has increased risk of gonadal germ cell neoplasms. Most of the literature focus on 45,X/46,XY gonadal dysgenesis, while there are scanty data on the condition when the karyotype is non-mosaic 46,XY. OBJECTIVE: To investigate the diversity of clinical pictures of children presenting with 46,XY DSD due to gonadal dysgenesis. METHODS: A retrospective study on consecutive patients diagnosed with 46,XY gonadal dysgenesis at age ≤18 years in a tertiary center from 1985 to 2015. The clinical presentations, phenotypes, gonadal features and associated anomalies were investigated. RESULTS: Twenty-eight patients with Y-chromosome gonadal dysgenesis were identified during the study period and six (21.4%) had non-mosaic 46,XY karyotype. Three had complete gonadal dysgenesis (CGD) with normal female phenotype, while the other three had partial gonadal dysgenesis (PGD). Of the three patients with CGD, two presented with the classical Swyer syndrome at adolescence, while the third presented at birth with multiple congenital anomalies. The three PGD patients presented with ambiguous genitalia at birth (n = 2), and isolated hypospadias (n = 1), which was associated with Frasier syndrome. Three patients had germ cell neoplasms: bilateral gonadoblastoma (n = 1), bilateral intratubular germ cell neoplasia unclassified (n = 1), and dysgerminoma + gonadoblastoma (n = 1). Two patients had global developmental delay with other congenital anomalies, and another patient had learning difficulties with borderline intelligence (Table). DISCUSSION: The findings suggest that 46,XY gonadal dysgenesis is much rarer than 45,X/46,XY gonadal dysgenesis. Patients differed in their clinical presentations and well-established syndromes happened in half of them. Overall, the risk of germ cell neoplasms and the association with other somatic anomalies appeared to be high. The study was limited by: its small number, single-center experience, and the possibility of missing the diagnosis in some male patients with mild undervirilization. CONCLUSION: Heterogeneity was noted in the clinical, phenotypic and gonadal features among pediatric patients with 46,XY gonadal dysgenesis.

Epigenetic silencing of GDF1 disrupts SMAD signaling to reinforce gastric cancer development.

Accumulating evidence reveals the effectiveness of epigenetic therapy in gastric cancer. However, the molecular mechanisms and targets underlying such therapeutic responses remain elusive. Herein, we report an aberrant yet therapeutically rectifiable epigenetic signaling in gastric carcinogenesis. Administration of DNA-demethylating drug 5-aza-2'-deoxycytidine (5-aza-dC) reduced gastric cancer incidence by ~74% (P < 0.05) in N-nitroso-N-methylurea-treated mice. Through genome-wide methylation scanning, novel promoter hypermethylation-silenced and drug-targeted genes were identified in the resected murine stomach tumors and tissues. We uncovered that growth/differentiation factor 1 (Gdf1), a member of the transforming growth factor-ß superfamily, was silenced by promoter hypermethylation in control tumor-bearing mice, but became reactivated in 5-aza-dC-treated mice (P < 0.05). In parallel, the downregulated SMAD2/3 phosphorylation in gastric cancer was revived by 5-aza-dC in vivo. Such hypermethylation-dependent silencing and 5-aza-dC-mediated reactivation of GDF1-SMAD2/3 activity was conserved in human gastric cancer cells (P < 0.05). Subsequent functional characterization further revealed the antiproliferative activity of GDF1, which was exerted through activation of SMAD2/3/4-mediated signaling, transcriptional controls on p15, p21 and c-Myc cell-cycle regulators and phosphorylation of retinoblastoma protein. Clinically, hypermethylation and loss of GDF1 was significantly associated with reduced phosphorylated-SMAD2/3 and poor survival in stomach cancer patients (P < 0.05). Taken together, we demonstrated a causal relationship between DNA methylation and a tumor-suppressive pathway in gastric cancer. Epigenetic silencing of GDF1 abrogates the growth-inhibitory SMAD signaling and renders proliferation advantage to gastric epithelial cells during carcinogenesis. This study lends support to epigenetic therapy for gastric cancer chemoprevention and identifies a potential biomarker for prognosis.

Inherited metabolic diseases in the Southern Chinese population: spectrum of diseases and estimated incidence from recurrent mutations.

Inherited metabolic diseases (IMDs) are a large group of rare genetic diseases. The spectrum and incidences of IMDs differ among populations, which has been well characterised in Caucasians but much less so in Chinese. In a setting of a University Hospital Metabolic Clinic in Hong Kong, over 100 patients with IMDs have been seen during a period of 13 years (from 1997 to 2010). The data were used to define the spectrum of diseases in the Southern Chinese population. Comparison with other populations revealed a unique spectrum of common IMDs. Furthermore, the incidence of the common IMDs was estimated by using population carrier frequencies of known recurrent mutations. Locally common diseases (their estimated incidence) include (1) glutaric aciduria type 1 (∼1/60,000), (2) multiple carboxylase deficiency (∼1/60,000), (3) primary carnitine deficiency (∼1/60,000), (4) carnitine-acylcarnitine translocase deficiency (∼1/60,000), (5) glutaric aciduria type 2 (∼1/22,500), (6) citrin deficiency (∼1/17,000), (7) tetrahydrobiopterin-deficient hyperphenylalaninaemia due to 6-pyruvoyl-tetrahydropterin synthase deficiency (∼1/60,000), (8) glycogen storage disease type 1 (∼1/150,000). In addition, ornithine carbamoyltransferase deficiency and X-linked adrenoleukodystrophy are common X-linked diseases. Findings of the disease spectrum and treatment outcome are summarised here which may be useful for clinical practice. In addition, data will also be useful for policy makers in planning of newborn screening programs and resource allocation.

The Janus face of cathelicidin in tumorigenesis.

Cathelicidin is a host defense peptide with multiple innate immunity-related functions. Recent findings indicate that cathelicidin is frequently dysregulated in human cancers where it plays a paradoxical yet dominant role in the regulation of tumor malignancy. In this review, the regulation of malignant phenotypes by cathelicidin in relation to the activation of its receptors and intracellular signaling is discussed.

Somatostatin receptor 1, a novel EBV-associated CpG hypermethylated gene, contributes to the pathogenesis of EBV-associated gastric cancer.

BACKGROUND: Somatostatin receptor 1 (SSTR1) was preferentially methylated in Epstein-Barr virus (EBV)-positive gastric cancer using promoter methylation array. We aimed to analyse the epigenetic alteration and biological function of SSTR1 in EBV-associated gastric cancer (EBVaGC). METHODS: Promoter methylation was examined by combined bisulphite restriction analysis (COBRA) and pyrosequencing. The biological functions of SSTR1 were evaluated by loss- and gain-of-function assays. RESULTS: Promoter hypermethylation of SSTR1 was detected in EBV-positive gastric cancer cell lines (AGS-EBV) with SSTR1 transcriptional silence, but not in EBV-negative gastric cancer cell lines with SSTR1 expression. Expression level of SSTR1 was restored in AGS-EBV by exposure to demethylating agent. Moreover, methylation level of SSTR1 was significantly higher in EBV-positive primary gastric cancers compared with EBV-negative gastric cancers (P=0.004). Knock-down of SSTR1 in gastric cancer cell lines (AGS and BGC823) increased cell proliferation and colony formation ability, and promoted G1 to S-phase transition, enhanced cell migration and invasive ability. In contrast, ectopic expression of SSTR1 in gastric cancer cell lines (MKN28 and MGC803) significantly suppressed cell growth in culture conditions and reduced tumour size in nude mice. The tumour suppressive effect of SSTR1 was associated with upregulation of cyclin-dependent kinase inhibitors (p16, p15, p27 and p21); downregulation of oncogenes (MYC and MDM2), key cell proliferation and pro-survival regulators (PI3KR1, AKT, BCL-XL and MET); and inhibition of the migration/invasion-related genes (integrins, MMP1 (matrix metallopeptidase 1), PLAUR (plasminogen activator urokinase receptor) and IL8 (interleukin 8)). CONCLUSION: Somatostatin receptor 1 is a novel methylated gene driven by EBV infection in gastric cancer cells and acts as a potential tumour suppressor.

Cathelicidin protects against Helicobacter pylori colonization and the associated gastritis in mice.

Cathelicidin, an antimicrobial peptide of the innate immune system, has been shown to modulate microbial growth, wound healing and inflammation. However, whether cathelicidin controls Helicobacter pylori infection in vivo remains unexplored. This study sought to elucidate the role of endogenous and exogenous mouse cathelicidin (CRAMP) in the protection against H. pylori infection and the associated gastritis in mice. Results showed that genetic ablation of CRAMP in mice significantly increased the susceptibility of H. pylori colonization and the associated gastritis as compared with the wild-type control. Furthermore, replenishment with exogenous CRAMP, delivered via a bioengineered CRAMP-secreting strain of Lactococcus lactis, reduced H. pylori density in the stomach as well as the associated inflammatory cell infiltration and cytokine production. Collectively, these findings indicate that cathelicidin protects against H. pylori infection and its associated gastritis in vivo. Our study also demonstrates the feasibility of using the transformed food-grade bacteria to deliver cathelicidin, which may have potential clinical applications in the treatment of H. pylori infection in humans.