Machine learning approaches to identify systemic lupus erythematosus in anti-nuclear antibody-positive patients using genomic data and electronic health records

BACKGROUND

Although the 2019 EULAR/ACR classification criteria for systemic lupus erythematosus (SLE) has required at least a positive anti-nuclear antibody (ANA) titer (≥ 1:80), it remains challenging for clinicians to identify patients with SLE. This study aimed to develop a machine learning (ML) approach to assist in the detection of SLE patients using genomic data and electronic health records.

METHODS

Participants with a positive ANA (≥ 1:80) were enrolled from the Taiwan Precision Medicine Initiative cohort. The Taiwan Biobank version 2 array was used to detect single nucleotide polymorphism (SNP) data. Six ML models, Logistic Regression, Random Forest (RF), Support Vector Machine, Light Gradient Boosting Machine, Gradient Tree Boosting, and Extreme Gradient Boosting (XGB), were used to identify SLE patients. The importance of the clinical and genetic features was determined by Shapley Additive Explanation (SHAP) values. A logistic regression model was applied to identify genetic variations associated with SLE in the subset of patients with an ANA equal to or exceeding 1:640.

RESULTS

A total of 946 SLE and 1,892 non-SLE controls were included in this analysis. Among the six ML models, RF and XGB demonstrated superior performance in the differentiation of SLE from non-SLE. The leading features in the SHAP diagram were anti-double strand DNA antibodies, ANA titers, AC4 ANA pattern, polygenic risk scores, complement levels, and SNPs. Additionally, in the subgroup with a high ANA titer (≥ 1:640), six SNPs positively associated with SLE and five SNPs negatively correlated with SLE were discovered.

CONCLUSIONS

ML approaches offer the potential to assist in diagnosing SLE and uncovering novel SNPs in a group of patients with autoimmunity.

Machine learning approaches for the genomic prediction of rheumatoid arthritis and systemic lupus erythematosus

BACKGROUND

Rheumatoid arthritis (RA) and systemic lupus erythematous (SLE) are autoimmune rheumatic diseases that share a complex genetic background and common clinical features. This study's purpose was to construct machine learning (ML) models for the genomic prediction of RA and SLE.

METHODS

A total of 2,094 patients with RA and 2,190 patients with SLE were enrolled from the Taichung Veterans General Hospital cohort of the Taiwan Precision Medicine Initiative. Genome-wide single nucleotide polymorphism (SNP) data were obtained using Taiwan Biobank version 2 array. The ML methods used were logistic regression (LR), random forest (RF), support vector machine (SVM), gradient tree boosting (GTB), and extreme gradient boosting (XGB). SHapley Additive exPlanation (SHAP) values were calculated to clarify the contribution of each SNPs. Human leukocyte antigen (HLA) imputation was performed using the HLA Genotype Imputation with Attribute Bagging package.

RESULTS

Compared with LR (area under the curve [AUC] = 0.8247), the RF approach (AUC = 0.9844), SVM (AUC = 0.9828), GTB (AUC = 0.9932), and XGB (AUC = 0.9919) exhibited significantly better prediction performance. The top 20 genes by feature importance and SHAP values included HLA class II alleles. We found that imputed HLA-DQA1*05:01, DQB1*0201 and DRB1*0301 were associated with SLE; HLA-DQA1*03:03, DQB1*0401, DRB1*0405 were more frequently observed in patients with RA.

CONCLUSIONS

We established ML methods for genomic prediction of RA and SLE. Genetic variations at HLA-DQA1, HLA-DQB1, and HLA-DRB1 were crucial for differentiating RA from SLE. Future studies are required to verify our results and explore their mechanistic explanation.

A Mobile Phone-Based Approach for Hearing Screening of School-Age Children: Cross-Sectional Validation Study

Background

Pure-tone screening (PTS) is considered as the gold standard for hearing screening programs in school-age children. Mobile devices, such as mobile phones, have the potential for audiometric testing.

Objective

This study aimed to demonstrate a new approach to rapidly screen hearing status and provide stratified test values, using a smartphone-based hearing screening app, for each screened ear of school-age children.

Method

This was a prospective cohort study design. The proposed smartphone-based screening method and a standard sound-treated booth with PTS were used to assess 85 school-age children (170 ears). Sound-treated PTS involved applying 4 test tones to each tested ear: 500 Hz at 25 dB and 1000 Hz, 2000 Hz, and 4000 Hz at 20 dB. The results were classified as pass (normal hearing in the ear) or fail (possible hearing impairment). The proposed smartphone-based screening employs 20 stratified hearing scales. Thresholds were compared with those of pure-tone average (PTA).

Results

A total of 85 subjects (170 ears), including 38 males and 47 females, aged between 11 and 12 years with a mean (SD) of 11 (0.5) years, participated in the trial. Both screening methods produced comparable pass and fail results (pass in 168 ears and fail in 2 ears). The smartphone-based screening detected moderate or worse hearing loss (average PTA>25 dB) accurately. Both the sensitivity and specificity of the smartphone-based screening method were calculated at 100%.

Conclusions

The results of the proposed smartphone-based self-hearing test demonstrated high concordance with conventional PTS in a sound-treated booth. Our results suggested the potential use of the proposed smartphone-based hearing screening in a school-age population.

Access Scheme for Controlling Mobile Agents and its Application to Share Medical Information

This study is showing the advantage of mobile agents to conquer heterogeneous system environments and contribute to a virtual integrated sharing system. Mobile agents will collect medical information from each medical institution as a method to achieve the medical purpose of data sharing. Besides, this research also provides an access control and key management mechanism by adopting Public key cryptography and Lagrange interpolation. The safety analysis of the system is based on a network attacker's perspective. The achievement of this study tries to improve the medical quality, prevent wasting medical resources and make medical resources access to appropriate configuration.

Design of a wireless sensor network platform for tele-homecare

The problem of an ageing population has become serious in the past few years as the degeneration of various physiological functions has resulted in distinct chronic diseases in the elderly. Most elderly are not willing to leave home for healthcare centers, but caring for patients at home eats up caregiver resources, and can overwhelm patients' families. Besides, a lot of chronic disease symptoms cause the elderly to visit hospitals frequently. Repeated examinations not only exhaust medical resources, but also waste patients' time and effort. To make matters worse, this healthcare system does not actually appear to be effective as expected. In response to these problems, a wireless remote home care system is designed in this study, where ZigBee is used to set up a wireless network for the users to take measurements anytime and anywhere. Using suitable measuring devices, users' physiological signals are measured, and their daily conditions are monitored by various sensors. Being transferred through ZigBee network, vital signs are analyzed in computers which deliver distinct alerts to remind the users and the family of possible emergencies. The system could be further combined with electric appliances to remotely control the users' environmental conditions. The environmental monitoring function can be activated to transmit in real time dynamic images of the cared to medical personnel through the video function when emergencies occur. Meanwhile, in consideration of privacy, the video camera would be turned on only when it is necessary. The caregiver could adjust the angle of camera to a proper position and observe the current situation of the cared when a sensor on the cared or the environmental monitoring system detects exceptions. All physiological data are stored in the database for family enquiries or accurate diagnoses by medical personnel.

A study on agent-based secure scheme for electronic medical record system

Patient records, including doctors' diagnoses of diseases, trace of treatments and patients' conditions, nursing actions, and examination results from allied health profession departments, are the most important medical records of patients in medical systems. With patient records, medical staff can instantly understand the entire medical information of a patient so that, according to the patient's conditions, more accurate diagnoses and more appropriate in-depth treatments can be provided. Nevertheless, in such a modern society with booming information technologies, traditional paper-based patient records have faced a lot of problems, such as lack of uniform formats, low data mobility, slow data transfer, illegible handwritings, enormous and insufficient storage space, difficulty of conservation, being easily damaged, and low transferability. To improve such drawbacks, reduce medical costs, and advance medical quality, paper-based patient records are modified into electronic medical records and reformed into electronic patient records. However, since electronic patient records used in various hospitals are diverse and different, in consideration of cost, it is rather difficult to establish a compatible and complete integrated electronic patient records system to unify patient records from heterogeneous systems in hospitals. Moreover, as the booming of the Internet, it is no longer necessary to build an integrated system. Instead, doctors can instantly look up patients' complete information through the Internet access to electronic patient records as well as avoid the above difficulties. Nonetheless, the major problem of accessing to electronic patient records cross-hospital systems exists in the security of transmitting and accessing to the records in case of unauthorized medical personnels intercepting or stealing the information. This study applies the Mobile Agent scheme to cope with the problem. Since a Mobile Agent is a program, which can move among hosts and automatically disperse arithmetic processes, and moves from one host to another in heterogeneous network systems with the characteristics of autonomy and mobility, decreasing network traffic, reducing transfer lag, encapsulating protocol, availability on heterogeneous platforms, fault-tolerance, high flexibility, and personalization. However, since a Mobile Agent contacts and exchanges information with other hosts or agents on the Internet for rapid exchange and access to medical information, the security is threatened. In order to solve the problem, this study proposes a key management scheme based on Lagrange interpolation formulas and hierarchical management structure to make Mobile Agents a more secure and efficient access control scheme for electronic patient record systems when applied to the access of patients' personal electronic patient records cross hospitals. Meanwhile, with the comparison of security and efficacy analyses being the feasibility of validation scheme and the basis of better efficiency, the security of Mobile Agents in the process of operation can be guaranteed, key management efficacy can be advanced, and the security of the Mobile Agent system can be protected.

Mobile agent application and integration in electronic anamnesis system

Electronic anamnesis is to transform ordinary paper trails to digitally formatted health records, which include the patient's general information, health status, and follow-ups on chronic diseases. Its main purpose is to let the records could be stored for a longer period of time and could be shared easily across departments and hospitals. Which means hospital management could use less resource on maintaining ever-growing database and reduce redundancy, so less money would be spent for managing the health records. In the foreseeable future, building up a comprehensive and integrated medical information system is a must, because it is critical to hospital resource integration and quality improvement. If mobile agent technology is adopted in the electronic anamnesis system, it would help the hospitals to make the medical practices more efficiently and conveniently. Nonetheless, most of the hospitals today are still using paper-based health records to manage the medical information. The reason why the institutions continue using traditional practices to manage the records is because there is no well-trusted and reliable electronic anamnesis system existing and accepted by both institutions and patients. The threat of privacy invasion is one of the biggest concerns when the topic of electronic anamnesis is brought up, because the security threats drag us back from using such a system. So, the medical service quality is difficult to be improved substantially. In this case, we have come up a theory to remove such security threats and make electronic anamnesis more appealing for use. Our theory is to integrate the mobile agent technology with the backbone of electronic anamnesis to construct a hierarchical access control system to retrieve the corresponding information based upon the permission classes. The system would create a classification for permission among the users inside the medical institution. Under this framework, permission control center would distribute an access key to each user, so they would only allow using the key to access information correspondingly. In order to verify the reliability of the proposed system framework, we have also conducted a security analysis to list all the possible security threats that may harm the system and to prove the system is reliable and safe. If the system is adopted, the doctors would be able to quickly access the information while performing medical examinations. Hence, the efficiency and quality of healthcare service would be greatly improved.

Spleen-preserving distal pancreatectomy

INTRODUCTION

Splenectomy is routinely performed in conventional distal pancreatectomies. Spleen removal with its possible sequelae of infections and haematological complications has prompted the development of spleen-preserving techniques. This study aimed to evaluate the safety and clinical outcomes of distal pancreatectomy with preservation of the spleen.

METHODS

A retrospective review of 24 consecutive patients who underwent spleen-preserving distal pancreatectomy in a tertiary care hospital was conducted.

RESULTS

There were 17 female and seven male patients, and the mean age was 47 (range 14-77) years. Median American Society of Anesthesiologists score was II (range I-III) . The indications were as follows : mucinous cystadenoma (n = 7), serous cystadenoma (n = 6), insulinoma (n = 3), intraductal papillary mucinous tumour (n = 2), pseudocyst (n = 3), papillary cystic adenoma (n = 1), neuroendocrine neoplasm (n = 1), and metastatic carcinoma of the thyroid (n = 1). Two patients developed postoperative pancreatic fistula and another two patients developed postoperative ileus with spontaneous resolution. Mean operative time was 172 (range 105-250) minutes. Mean length of postoperative hospital stay was 6.7 (range 5-11) days. There was no perioperative mortality in this series.

CONCLUSION

Spleen-preserving distal pancreatectomy can be safely performed with low morbidity, and should be considered in the surgical management of distal pancreatic disease.

Pedunculated HCC or adrenal metastasis: a diagnostic conundrum

Hepatocellular carcinoma (HCC) is the commonest primary liver tumour. Recurrences are common in the liver although extrahepatic metastases can occur and frequently involve the adrenals. When this occurs in the right adrenal gland, it can be confused with an exophytic HCC arising from the posterior surface of the liver. The distinction between a primary HCC and a metastasis is important but can be difficult in this clinical setting. We report a 52-year-old man with recurrent HCC presenting as an "exophytic" posterior liver surface lesion that was actually a right adrenal metastasis. Although right-sided adrenal metastases of HCC can be difficult to distinguish from intrahepatic recurrences, even with modern diagnostic imaging, management either way involves surgical exploration and resection whenever possible.

Clinical applications of MR cholangiopancreatography

INTRODUCTION

We review the clinical applications of magnetic resonance cholangiopancreatography (MRCP) and illustrate them with clinical examples.

METHODS

A literature search was performed in MedLine using the keywords "MR cholangiopancreatography" and "MRCP". The relevant articles were reviewed. The radiology information system was searched for MRCP examinations performed from July 1999 to December 2002. A surgical database of resected cases was also referenced. Illustrative cases were chosen in consultation with surgical authors to show the clinical applications of MRCP.

RESULTS

MRCP is useful for assessment of choledocholithiasis, choledochal cysts, pancreas divisum, primary sclerosing cholangitis, pancreatitis and anatomical variation of the biliary ducts. When complemented with dynamic gadolinium-enhanced studies, MRCP is useful for assessment of ductal cholangiocarcinoma, pancreatic and gall bladder neoplasms. Illustrative cases are provided.

CONCLUSION

MRCP is an important modality for the clinical assessment of biliary and pancreatic disorders.

Breath-hold fast recovery fast spin echo versus conventional non-breath-hold fast spin echo T2-weighted MR imaging of focal liver lesions

INTRODUCTION

We compare the breath-hold fast recovery fast spin echo (BHFRFSE) T2-weighted and non-breath-hold fast spin echo (NBHFSE) T2-weighted sequences in image quality and lesion characterisation of focal liver lesions.

MATERIALS AND METHODS

Fat-suppressed T2-weighted magnetic resonance (MR) images obtained with the 2 sequences (BHFRFSE and NBHFSE) in 79 patients with 113 liver lesions were analysed retrospectively. The image quality and nature of the lesions were evaluated by 2 experienced radiologists.

RESULTS

Based on receiver operating characteristic curve analysis, lesion characterisation was comparable for both sequences. The image quality of BHFRFSE was significantly better than that of NBHFSE. The NBHFSE missed 4 malignant lesions while BHFRFSE missed 2 malignant lesions.

CONCLUSION

BHFRFSE performs similarly to NBHFSE in image quality and liver lesion characterisation.

Identification of a novel cell cycle regulated gene, HURP, overexpressed in human hepatocellular carcinoma

An analytic strategy was followed to identify putative regulatory genes during the development of human hepatocellular carcinoma (HCC). This strategy employed a bioinformatics analysis that used a database search to identify genes, which are differentially expressed in human HCC and are also under cell cycle regulation. A novel cell cycle regulated gene (HURP) that is overexpressed in HCC was identified. Full-length cDNAs encoding the human and mouse HURP genes were isolated. They share 72 and 61% identity at the nucleotide level and amino-acid level, respectively. Endogenous levels of HURP mRNA were found to be tightly regulated during cell cycle progression as illustrated by its elevated expression in the G(2)/M phase of synchronized HeLa cells and in regenerating mouse liver after partial hepatectomy. Immunofluorescence studies revealed that hepatoma up-regulated protein (HURP) localizes to the spindle poles during mitosis. Overexpression of HURP in 293T cells resulted in an enhanced cell growth at low serum levels and at polyhema-based, anchorage-independent growth assay. Taken together, these results strongly suggest that HURP is a potential novel cell cycle regulator that may play a role in the carcinogenesis of human cancer cells.

Recurrent chromosomal rearrangements involving breakpoints 3p21 and 19q13 in Chinese IgD multiple myeloma detected by G-banding and multicolor spectral karyotyping: a review of IgD karyotype literature

Immunoglobulin D multiple myeloma (IgD MM) is a rare subtype that accounts for 1% to 3% of MM and shows higher aggressiveness with distinctive clinical and laboratory features. However, there is little information in the literature on their karyotypes, which are mainly derived from G-banding results. Our current study on 2 Chinese IgD MM thus represents the first description of cytogenetic data on this subtype based on an integrated analysis with G-banding and multicolor spectral karyotyping (SKY). Both of our cases showed some usual features of MM, as well as a few novel translocations including t(3;22), t(6;19), t(X;19) and the 3 whole-arm translocations namely t(1;6)(q10;p10), t(4;9)(q10;p10), and t(16;18)(q10;q10). We also identified recurrent chromosomal rearrangements involving breakpoints 3p21 and 19q13, which may suggest to be unique aberrations that may underline the pathogenesis of this distinctive biological MM subtype.

Management of intraparotid facial nerve schwannomas

BACKGROUND

The purpose of the present paper was to review the management of intraparotid facial nerve schwannoma so as to discuss its clinical presentation, evaluate the various possible diagnostic investigations, and compare the various surgical options and outcome.

METHODS

Case series was undertaken of five (1.3%) patients with facial nerve schwannoma out of 400 consecutive parotidectomies at Singapore General Hospital.

RESULTS

There were three men and two women with an age range of 29-65 years. Three patients presented with painless parotid lumps while two had painful parotid swellings. None had facial nerve paresis. Only one patient had preoperative diagnosis suspicious of schwannoma by fine-needle aspiration cytology (FNAC). Diagnoses were made intraoperatively. Four patients had excision with cable grafting of the nerve defect. achieving facial nerve grade II-IV (House-Brackmann scale). One patient who underwent enucleation of tumour with nerve preservation achieved grade II.

CONCLUSIONS

Preoperative diagnosis is difficult but it is important for discussion of the extent and options of surgery. Fine-needle aspiration cytology holds promise in making a preoperative diagnosis. Enucleation with nerve preservation where possible seems to offer better facial function whereas nerve excision with cable graft can give satisfactory results.

Diagnostic failures in endoscopy for acute upper gastrointestinal haemorrhage

BACKGROUND

Oesophagogastroduodenoscopy (OGD) is the diagnostic tool of choice in acute upper gastrointestinal haemorrhage. However, the factors causing diagnostic failure are not well documented or discussed.

METHODS

OGDs performed by a single surgeon for acute upper gastrointestinal haemorrhage were reviewed retrospectively for 'missed' diagnosis.

RESULTS

There were nine cases (1.4 per cent) of 'missed' diagnosis in 638 OGDs performed over a 3-year period. Incomplete examination caused by a fundal pool precluded three examinations in which two Dieulafoy's lesions and one chronic gastric ulcer were later found. Other difficult examination sites were the cardia/high lesser curve (three cases), the stomal line of a gastrojejunostomy anastomosis (two) and at the junction of the first and second part of the duodenum (one). Four of the overlooked diagnoses were Dieulafoy's lesions.

CONCLUSION

OGD was able to diagnose the cause of bleeding in 98.6 per cent of patients with acute upper gastrointestinal haemorrhage. The factors that caused diagnostic failure were a difficult examination site and failure to recognize lesions (Dieulafoy's).

Microdochectomy for single-duct nipple discharge

INTRODUCTION

Isolated single-duct nipple discharge is worrying and poses a surgical dilemma. Factors predicting malignancy are controversial.

MATERIALS AND METHODS

Retrospective review of 92 consecutive microdochectomies for single-duct nipple discharge in a tertiary referral centre over 8 years.

RESULTS

The commonest causes were ductal papilloma (52%) and fibrocystic diseases of the breast (21%). Five (5%) patients had breast carcinoma, of whom only 1 had an invasive component. The median age of these patients was 43 years (range 26 to 72 years) which was similar to median age of the whole cohort. Sixty-seven (73%) patients presented with blood-stained nipple discharge. The 5 patients with breast carcinoma had blood-stained discharge. Mammography was abnormal in 1 out of 4 patients in the carcinoma group.

CONCLUSIONS

The incidence of breast carcinoma in patients presenting with isolated single-duct nipple discharge was low (5%) among Singaporean women. There was no reliable predictors of malignancy, though all patients with carcinoma presented with blood-stained discharge. Microdochectomy still remains an effective treatment for nipple discharge both for cure and diagnosis.

Epidemiology of Warthin's tumour of the parotid gland in an Asian population

BACKGROUND

Recent studies have documented a number of changing demographic features in the occurrence of Warthin's tumour (adenolymphoma) of the parotid gland. In order to analyse its epidemiology in an Asian population, a retrospective study was performed on all parotid neoplasms (n = 289) operated on between 1988 and 1998.

PATIENTS AND METHODS

A total of 209 consecutive patients were selected for study, 136 with pleomorphic adenomas (one bilateral) and 73 with Warthin's tumours (seven bilateral). Patients were analysed with regard to tumour incidence, age, sex and race. Smoking as an aetiological factor in the development of Warthin's tumour was also studied.

RESULTS

Warthin's tumour formed 25 per cent of parotid tumours and its ratio to pleomorphic adenomas was 1 : 1.9. Multicentricity was found in 14 patients (19 per cent). The male : female ratio for Warthin's tumours was 4.6 : 1. The proportion of Warthin's tumours did not show any increasing trend relative to pleomorphic adenomas. The racial distribution of Warthin's tumours showed an increased incidence among Chinese and a reduced incidence among Malays and Indians. The adjusted odds ratio for sex and age favouring an association between smoking and Warthin's tumour was 39.5 (95 per cent confidence interval 10.5-149. 0; P < 0.0001).

CONCLUSION

The incidence of Warthin's tumour is considerable among Asians although there is still male predominance. There is no rising incidence of Warthin's tumour; the trend parallels the declining smoking rate in the population. The lower incidence among ethnic groups with dark skin seems to suggest concomitant genetic factors other than environmental factors alone in histogenesis. Smokers have a 40-fold greater risk than non-smokers of developing a Warthin's tumour.

Splenic angiosarcoma--an unusual cause of bleeding gastrointestinal tract

Splenic angiosarcoma is a rare malignant vascular tumour with about 100 reported cases to date. The presentation of splenic angiosarcoma is highly variable, frequently causing diagnostic difficulty. It usually presents with splenomegaly, abdominal pain and occasionally with a microangiopathic type of anaemia. Here we report an additional case of primary angiosarcoma of the spleen presenting as a problem of bleeding from the gastrointestinal tract.

Minimizing recurrence after sigmoid volvulus

BACKGROUND

This study was a retrospective review of a series of patients with sigmoid volvulus to identify risk factors for recurrence and recommend appropriate treatment.

METHODS

Thirty-five patients with sigmoid volvulus were treated over 8 years.

RESULTS

Six patients had emergency surgery for peritonitis. Twenty-eight of the other 29 patients had successful endoscopic decompression; 15 of these patients had elective surgery during the same admission. Twelve of the 14 patients who refused operation after endoscopic decompression developed recurrent volvulus, a median of 2.8 months later. Eight subsequently agreed to surgery and underwent elective operation following repeat decompression. Of 29 patients who had surgery, 27 had sigmoid colectomy (two were initial Hartmann procedures) and two had subtotal colectomy. Six patients who had sigmoid colectomy developed recurrent volvulus. Concomitant megacolon and megarectum at the time of initial surgery were significant predictors of recurrence.

CONCLUSION

Subtotal colectomy, carried out as the primary procedure if there is concomitant megacolon or megarectum, might reduce the risk of recurrent sigmoid volvulus.

Combined morphological and interphase fluorescence in situ hybridization study in multiple myeloma of Chinese patients

To gain insight into the real incidence of the numeric chromosomal aberrations and the cell lineage involvement of the neoplastic process in multiple myeloma (MM), we examined 18 Chinese MM patients by May-Grunwald-Giemsa (MGG) staining and fluorescence in situ hybridization using three DNA centromeric probes specific for chromosomes 3, 7, and 9. In this investigation, cytogenetic abnormalities were detected in plasma cells (PCs), myeloid cells (MCs), and lymphoid cells (LCs) in all of the MM patients studied. This is the first demonstration of the cytogenetic aberration involved in the myeloid series. Furthermore, the MCs and PCs of 16 MM patients had the same aneuploidies in one or more of the chromosomes analyzed. These data suggest that the neoplastic transformation of MM may occur early in the hematopoietic development. Chromosomal aberrations involving mainly subclones and considerable cellular heterogeneity with gain of a variety of copy numbers of the same chromosome were demonstrated within PCs, which may possibly be the result of an underlying defect of PCs in the control of their number of chromosomes. Whereas PCs showed evidence suggestive of increased polyploidization, MCs and LCs, which exhibited similar chromosomal patterns as the former, rarely did. Thus, the clonal evolution from LC to PC, if that happens in MM, is characterized by chromosomal instability favoring growth of tumor cells with polysomies and polyploidies.

Transcriptional silencing of the p16 gene in human myeloma-derived cell lines by hypermethylation

Recently, p16 and p15 have been identified as commonly inactivated tumour suppressor genes in haematological malignancies. We previously reported that these genes were frequently hypermethylated in multiple myeloma (MM). To investigate how p16 and p15 inactivation are associated with hypermethylation, methylation status and transcription of these genes in six MM-derived cell lines were studied by Southern blot analysis and RT-PCR. Aberrant methylation of p16 was found in ARH-77, HS-Sultan, IM-9, RPMI-8226, U266-B1 and NCI-H929 MM cell lines. However, loss of p16 transcription was demonstrated only in HS-Sultan, RPMI-8226, U266-B1 and NCI-H929 with extensive methylation at the 5' upstream region of p16. Conversely, only HS-Sultan showed extensive methylation at the 5' upstream region of p15, which was associated with p15 transcriptional block. These results suggest that extensive methylation within a critical domain may be crucial in silencing p16 or p15 transcription. To demonstrate the reversibility of methylation and its relationship with transcription, HS-Sultan, RPMI-8226 and NCI-H929 were demethylated with 5-aza-2'-deoxycytidine. Restoration of gene transcription was observed and correlated with partial demethylation of the genes. The present data show that the p16 and p15 genes are silenced in MM by hypermethylation, which may play an important role in MM pathogenesis.

Young age is not a poor prognostic marker in colorectal cancer

BACKGROUND

There is still considerable controversy and debate regarding the features and prognosis of colorectal cancer in young patients.

METHODS

One hundred and ten patients (5.1 per cent) under the age of 40 years with colorectal cancer (group Y; male: female ratio 48:62) were compared with 2064 patients with colorectal cancer aged 40 years or more (group O; 917 women, 1147 men). Mode of presentation, stage at diagnosis, tumour characteristics and survival were analysed.

RESULTS

Predisposing malignant conditions and family history of colorectal cancer were present in 20.9 per cent of patients in group Y versus 2.2 per cent in group O (P < 0.001). Common chief complaints included change in bowel habits, bleeding from the rectum and a significantly higher incidence of abdominal pain in group Y. There was no difference in stage at presentation between the two groups (the proportion of Dukes stage A, B, C and 'D' lesions in group Y was 8.2, 24.5, 37.3 and 30.0 per cent respectively versus 10.5, 27.9, 33.4 and 28.1 per cent in group O). Tumour site and characteristics were similar in both groups. The incidence of mucinous/signet ring cell and poor grade tumours was 6.9 and 11.8 per cent respectively in group Y and 4.5 and 10.5 per cent in group O. With a mean follow-up of 31.8 months, the overall 5-year survival rate was 54.8 per cent in group Y and 54.1 per cent in group O. Comparing stage for stage, survival was not significantly different in the two groups. However, the adjusted hazard ratios of the age groups Y, M (40-59 years), S (60-79 years), and E (80 years and above) were 1.3, 1 (baseline for calculations), 1.4 and 2.4 respectively, suggesting an adverse outcome for patients in group Y compared with patients aged 40-59 years.

CONCLUSION

This study revealed no difference in tumour characteristics and survival in patients with colorectal cancer aged less than 40 years compared with those aged above 40 years. However, a higher hazard ratio in the youngest group may connote a worse prognosis than that for those aged 40-59 years. A significant family history of colorectal cancer and predisposing conditions in the young warrants aggressive screening, surveillance and treatment of the underlying conditions. The detection of colorectal cancer in young patients should be no different from that in the old but demands a high index of suspicion.

Management of colonic lipomas

BACKGROUND

Little is known of colonic lipomas, especially in an Asian population, and their management is controversial.

METHODS

A computerized colonoscopy database was analysed and patients with colonic lipomas were reviewed.

RESULTS

There were 16 colonic lipomas (incidence of 0.15%) in a series of 10658 consecutive colonoscopies. There were seven men and nine women, with a mean age of 61.8 years (range: 28-80 years). The size of the lipomas ranged from 1.5 to 6 cm; all those larger than 3.5 cm were symptomatic (P = 0.05). The most common symptom was mild bleeding per rectum. Right-sided lipomas were palpable while left-sided lipomas presented with obstructive symptoms. Colonoscopic removal by hot biopsy or snare polypectomy was possible where the lipomas were 2.5 cm and pedunculated. Surgery was performed in six patients (four open, two laparoscopic) for symptoms and to exclude malignancy. There was no morbidity or mortality.

CONCLUSIONS

Small or pedunculated lipomas may be safely removed colonoscopically and the diagnosis confirmed histologically. Larger lipomas require surgical resection for relief of symptoms or to exclude malignancy.

Frequent hypermethylation of p16 and p15 genes in multiple myeloma

Both p16 and p15, encoded by the genes located on chromosome 9p21, are inhibitors of cyclin-dependent kinases (CDK4/6) and the upstream regulators of Rb function. In hematopoietic malignancies, deletion of p16/p15 locus has been shown to be highly specific to lymphoid, and more particularly from B-lineage malignancies except multiple myeloma (MM). To investigate whether these genes are inactivated by deletions, mutations, and hypermethylation of the 5' CpG islands, we examined 12 MM patients by Southern hybridization and polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis. No deletions nor mutations of the p16 and p15 genes were found. However, hypermethylation was observed in 75% for p16 and 67% for p15 in our group of MM patients. Such high frequencies of involvement of these genes in MM make them hitherto the most common genetic abnormalities in this disease. Concomitant hypermethylation, uncommon thus far in the literature of the study of these genes, is a rather common phenomenon, occurring in 67% of our patient group. Moreover, hypermethylation of p16/p15 was associated with blastic disease and concomitant hypermethylation of both genes may be pathogenetically related to plasmacytoma development. These results indicate that these genes are important in MM pathogenesis. Here we report, for the first time in the literature, the high incidences of p16 and p15 alterations in MM, not by homozygous deletions or mutations, but solely by hypermethylation of the 5' CpG islands, which may be a specific mechanism in this disease.

Pediatric nosocomial fungal infections

During a period of twelve years (1984-1995), ninety-seven pediatric patients experienced 107 nosocomial fungal infections at Mackay Memorial Hospital. The nosocomial fungal infection rate in pediatric patients was lower than that of the hospital as whole, but it increased significantly. The average rate in the last three years (1993-1995) was 1.20 per thousand discharged patients, 10 times that of the first three years (1984-1986). Two-thirds of the patients were below one year of age. Half of the infections occurred in Intensive Care Units. The bloodstream was the most common site of infection (40.2%), followed by the urinary tract and skin. Important underlying diseases included malignancies, prematurity, and congenital anomalies. Common risk procedures included total parenteral nutrition (43.3%), endotracheal intubation (29.9%), central venous catheterization (25.8%), operation (14.4%). Near 90% of the patients had previously received antibiotics. Candida albicans was responsible for 58.1% of the infections. Thirty-three patients expired, of whom 18 died of the fungal infections. With the trend of increasing nosocomial fungal infections, physicians should be more alert to the possibility of such infections.

Hypermethylation of the p16 gene in nasopharyngeal carcinoma

We have recently reported that inactivation of the p16 gene by mutation and deletion is common in nasopharyngeal carcinoma (NPC). The present study demonstrates that hypermethylation of the 5' CpG island can serve as an alternative mechanism for inactivation of the p16 gene in this tumor. Using Southern blotting analysis and multiplex PCR, aberrant methylation of the 5' CpG island of the p16 gene was found in a NPC xenograft (xeno-666) and 6 (22%) of 27 primary tumors, but not in normal tissues of the nasopharynx. In the NPC xenograft (xeno-666) and its newly derived cell line (cell-666), both showing hypermethylation of the p16 gene, no p16 gene expression was found. After treatment with 5-aza-2'-deoxycytidine, reexpression of the p16 gene was detected in the cell line cell-666. These findings suggest that aberrant methylation of the 5' CpG island may participate in the transcriptional inactivation of the p16 gene in NPC. The present results further support that the p16 gene is the critical target on chromosome 9p21 for inactivation during the development of this disease.