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Featured researches published by T.Y. Ng.


Journal of Clinical Oncology | 1999

Chemoradiation and Adjuvant Chemotherapy in Cervical Cancer

L.C. Wong; Hys Ngan; A. N.Y. Cheung; D. K.L. Cheng; T.Y. Ng; D. T.K. Choy

PURPOSE Radiotherapy is the standard treatment for locally advanced cervical cancer, but treatment results remain disappointing, particularly for women with bulky central disease. We investigated the role of concurrent chemoradiation and adjuvant chemotherapy in a randomized trial. PATIENTS AND METHODS Two hundred twenty patients with bulky stage I, II, and III cervical cancer were randomized to receive either standard pelvic radiotherapy or chemoradiation (epirubicin 60 mg/m(2)) followed by adjuvant chemotherapy with epirubicin 90 mg/m(2) administered at 4-week intervals for five additional cycles. RESULTS Fifty-nine patients have relapsed, with a median follow-up duration of 77 months. Patients who received epirubicin radiation therapy showed a significantly longer disease-free (P =.03) and cumulative survival (P =.04). Patients who received radiation alone had significantly more distant metastasis than those who received chemoradiation (P =.012). There was no difference in long-term local tumor control (P =.99). CONCLUSION Survival benefit has been demonstrated in patients treated with chemoradiation followed by adjuvant chemotherapy with epirubicin as compared with patients treated with standard pelvic radiotherapy alone.


European Journal of Cancer | 2003

E-cadherin expression is silenced by DNA methylation in cervical cancer cell lines and tumours

C.-L. Chen; Stephanie S. Liu; Sin-Ming Ip; L.C. Wong; T.Y. Ng; Hys Ngan

A previous study showed E-cadherin expression was lost in some cervical cancer cell lines and tumours. This study was designed to clarify the significance of DNA methylation in silencing E-cadherin expression. We examined promoter methylation of E-cadherin in five cervical cancer cell lines and 20 cervical cancer tissues using methylation-specific PCR (MSP) and bisulphite DNA sequencing. The correlation of E-cadherin methylation and expression together with methyltransferase (DNMT1) were further studied. We found that hypermethylation of E-cadherin was involved in five cervical cancer cell lines and 40% (8/20) of cervical cancer tissues. E-cadherin protein was lost in 6/8 (75%) samples and 3/5 (60%) cell lines with promoter methylation. E-cadherin methylation was significantly correlated with increased DNMT1. Using an antisense DNMT1 oligo to transfect into SiHa HeLa C33A cell line, E-cadherin protein was re-expressed. We concluded that loss of E-cadherin expression was in part correlated with DNA methylation and DNMT1 expression in cervical cancer.


European Journal of Cancer | 2001

Anti-apoptotic proteins, apoptotic and proliferative parameters and their prognostic significance in cervical carcinoma

Stephanie S. Liu; B.K Tsang; Any Cheung; Wei-Cheng Xue; Danny K.L. Cheng; T.Y. Ng; L.C. Wong; Hys Ngan

The inhibitor of apoptosis proteins (IAP) suppress apoptosis induced by a variety of stimuli. The aims of this study were to: (a) compare the expression of X-linked IAP (Xiap) and Human IAP-2 (Hiap-2) in cervical carcinoma cells and normal cervix, (b) determine the correlation between IAP expression and tumour apoptosis or proliferation, and (c) assess their prognostic significance in cervical carcinomas. Paraffin-embedded tissue sections were retrieved from 77 patients with cervical squamous carcinomas prior to treatments and 47 normal subjects. Tumour apoptosis was determined by terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuracil triphosphate (dUTP) nick-end labelling (TUNEL) and apoptotic index (AI), and the proliferative rate was measured by Ki-67 and mitotic (MI) indices. Immunoreactive Xiap and Hiap-2 were found in both cervical cancer cells and normal tissues. IAP expressions in cancers did not correlate with apoptotic and proliferative parameters, disease stage and patient survival. The lower AI and Ki-67 index were associated with a better survival. In conclusion, the basal expression levels of IAPs have no prognostic significance, but AI and Ki-67 expression are potential prognostic indicators in cervical carcinoma.


Clinical Cancer Research | 2004

p73 expression is associated with the cellular radiosensitivity in cervical cancer after radiotherapy.

Stephanie S. Liu; Rebecca Ching-Yu Leung; Kelvin Yuen-Kwong Chan; Pui-Man Chiu; Annie N.Y. Cheung; Kar-Fai Tam; T.Y. Ng; Ling-Chui Wong; Hys Ngan

Apoptosis is one of the causes of cell death in cervical cancer following radiotherapy (S. S. Liu et al., Eur. J. Cancer, 37: 1104–1110, 2001). By studying the gene expression profile with cDNA apoptotic array, the p73 gene was found overexpressed in radiosensitive cervical cancers when compared with radioresistant ones. To investigate the role of the p73 gene in relation to clinical assessment of radiosensitivity in cervical cancer based on the findings of residual tumor cells in cervical biopsies after completion of radiotherapy, we studied the protein expression of p73 in 59 cervical cancers after radiotherapy and 68 normal cervices using immunohistochemistry. The expression of p73 was found to be significantly increased in cancer samples and, more importantly, in those samples sensitive to radiotherapy (P < 0.001). The overexpression of p73 actually predicted a better prognosis in cervical cancer patients (P < 0.001). To investigate the possible involvement of p73 downstream genes, the protein expressions of p21 and Bax were studied. The expression of p21, but not Bax, was found to be positively correlated with the expression of p73 (P = 0.001). Furthermore, the epigenetic regulation of p73 expression via DNA methylation was also investigated in 103 cervical cancers and 124 normals. Hypermethylation of p73 gene was observed in 38.8% of cervical cancers, and it was significantly associated with reduced or absent p73 expression (P < 0.001). Reactivation of p73 expression in two cervical cancer cell lines by demethylation treatment supported the role of methylation in the regulation of p73 expression. Our findings suggested that p73 expression was related to the radiosensitivity of cervical cancer cells and may play an important role in the regulation of cellular radiosensitivity.


British Journal of Cancer | 2003

High frequency of mitochondrial genome instability in human endometrial carcinomas

Vincent W.S. Liu; Hui-Juan Yang; Y Wang; Percy C.K. Tsang; Annie N.Y. Cheung; Pui Man Chiu; T.Y. Ng; Ling Chui Wong; Phillip Nagley; Hys Ngan

To investigate the occurrence of somatic mitochondrial DNA (mtDNA) mutations in human primary endometrial carcinomas, we sequenced the D-loop region, the 12S and 16S rRNA genes of mtDNA of cancer tissues and their matched normal controls. About 56% (28 out of 50) of cases carry one or more somatic changes in mtDNA including deletion, point mutation and mitochondrial microsatellite instability (mtMSI), namely the change in length of short base-repetitive sequences of mtDNA. In particular, mtMSI was frequently detected in 89% (25 out of 28) of all the cases carrying somatic changes followed by point mutations (25%; seven out of 28) and deletion (3.5%; one out of 28). The CCCCCTCCCC sequences located in the Hypervariable Regions I and II of the D-loop and 12S rRNA gene are instability hot spot regions in endometrial carcinomas. It is suggested that errors in replication may account for the high frequency of mtMSI in human endometrial carcinomas. The relatively high prevalence of mtMSI may be a potential new tool for detection of endometrial cancer.


Tumor Biology | 2001

Abnormal expression of epidermal growth factor receptor and c-erbB2 in squamous cell carcinoma of the cervix: correlation with human papillomavirus and prognosis.

Hys Ngan; Any Cheung; Stephanie S. Liu; Danny K.L. Cheng; T.Y. Ng; L.C. Wong

The aim of this study is to assess the expression of epidermal growth factor receptor (EGFR) and c-erbB2 and their correlation with human papillomavirus (HPV) status and prognosis in squamous cell carcinoma of the cervix. The expression of EGFR and c-erbB2 was studied at the protein level using the immunohistochemical (IHC) staining method, at the RNA level using the ribonuclease protection assay and at the DNA level using Southern blot and hybridization method. One hundred and one patients with squamous cell carcinoma of the cervix were recruited. Fifty-one patients were of stage 1B/2A and 50 patients were of stage 2B and above. Positive IHC stainings of EGFR and c-erbB2 proteins were found in 74.2 and 19.8% of cases, respectively. DNA amplifications of EGFR and c-erbB2 genes were detected in 35.4 and 17.2%, respectively. Of the patients showing positive EGFR and c-erbB2 staining, only 39.2 and 25%, respectively, showed DNA amplifications. RNA overexpression of EGFR or c-erbB2 was only detected in 2% of cervical cancers and was associated with positive staining and DNA amplifications. HPV was detected in 79.2% of the cases by HPV consensus primers L1, in 57.4% for HPV 16 and 27.7% for HPV 18. The abnormal expression of EGFR and c-erbB2 had no correlation with HPV detection and had no prognostic significance on survival.


Tumor Biology | 1997

Prognostic significance of tumour markers in endometrial cancer

S.S.T. Lo; Danny K.L. Cheng; T.Y. Ng; L.C. Wong; Hys Ngan

Serum cancer antigen (CA) 125, CA15.3, CA19.9, carcinoembryonic antigen and tissue polypeptide antigen were analyzed in 100 normal subjects, 47 patients with benign gynaecological diseases and 97 patients with endometrial cancer. The incidence of individual elevated tumour markers (> 2SD) was 21.5-30.9% in cancer patients. Elevations of CA125 and CA15.3 were significantly associated with poor prognostic clinical factors. Univariate anaylses showed that elevated CA125, CA15.3 and CA19.9 were significantly associated with shorter survival. In multivariate analysis, CA15.3 was highly significant and had a larger hazard ratio. In conclusion, CA15.3 is a useful marker for the prognosis of patients with endometrial cancer.


Gynecologic Oncology | 2003

Symptoms, coping strategies, and timing of presentations in patients with newly diagnosed ovarian cancer.

Y.M. Chan; T.Y. Ng; Peter W. H. Lee; Hys Ngan; L.C. Wong

OBJECTIVE The purpose was to explore whether health education on symptoms of ovarian cancer would aid in early detection, by examining the relationship between symptoms, coping strategies, and timing of presentation in patients with newly diagnosed ovarian cancer. METHODS Eighty women were included. A questionnaire consisting of a series of open questions was designed to collect information on the sequence of events from the onset of symptoms to the diagnosis of ovarian cancer. The Coping Response Inventory (CRI) was used to assess the coping strategies. RESULTS A majority (90.0%) of women with ovarian cancer did have symptoms before the diagnosis. Abdominal pain or discomfort, abdominal distension, a palpable abdominal mass, menstrual, bowel, or urinary symptoms were the commonly reported symptoms. Eight (10.0%) patients were totally asymptomatic prior to the cancer diagnosis. The presence of bowel symptoms was significantly associated with late stage disease. Most of the patients sought medical advice within 2 weeks from the onset of symptoms. There was no association between the presence of any particular symptom(s) and the timing of presentation. There was also no correlation between the coping strategies and stage of disease and timing of presentation. On average, patients with early stage disease saw one more doctor compared to patients with late stage disease before the affirmative diagnosis of ovarian cancer. CONCLUSION Most patients presented early after the onset of symptoms. Health education in this regard may not be useful for early diagnosis of ovarian cancer.


Tumor Biology | 2003

Comparison of Human Papillomavirus DNA Levels in Gynecological Cancers: Implication for Cancer Development

Hui-Juan Yang; Vincent W.S. Liu; Percy C.K. Tsang; Ann M.W. Yip; T.Y. Ng; Annie N.Y. Cheung; Hys Ngan

We have previously demonstrated the presence of human papillomavirus (HPV) DNA in several gynecological cancers using conventional PCR. In the present study, to further understand the role of HPV in malignant transformation of these cancers, the infection rates and viral loads of HPV 16 and 18 in gynecological cancers were analyzed using real-time quantitative PCR (qPCR). HPV 16 DNA was detected in 61.0% (58/95), 15.2% (7/46) and 32.1% (18/56) of cases of cervical, endometrial and ovarian cancers, respectively. On the other hand, HPV 18 DNA was detected in 23.2% (22/95) of cervical cancers, 1.8% (1/56) of ovarian cancers, and in no cases of endometrial cancer. Thus, HPV 16 is much more prevalent than HPV 18 in malignancies of the female genital tract. We also found that both HPV 16 and 18 were significantly (p < 0.05) less frequently present in endometrial and ovarian cancers than in cervical cancer. The median copy numbers of HPV 16 DNA in endometrial and ovarian cancers were 3,500 and 7,590 copies/µg DNA, respectively. These amounts were also significantly (p < 0.05) lower than HPV 16 DNA in cervical cancer (492,800 copies/µg DNA). Thus, HPV 16 could be detected in all three types of gynecological cancer, whilst HPV 18 is extremely rare in endometrial and ovarian cancers. The lower HPV 16 infection rates and lower copy numbers when compared with cervical cancer tend to suggest that HPV plays a less essential role in the development of endometrial cancer and ovarian cancer.


Supportive Care in Cancer | 2005

The behaviors of seeking a second opinion from other health-care professionals and the utilization of complementary and alternative medicine in gynecologic cancer patients

Kar-Fai Tam; Danny K.L. Cheng; T.Y. Ng; Hys Ngan

Goals of workThe aim of the study is to determine the predictors for seeking a second opinion and the utilization of complementary and alternative medicine (CAM) among gynecologic cancer patients.Patients and methodsPatients attending a gynecologic cancer clinic of a tertiary referral center were recruited over a period of 1 year. A survey was conducted for all the participants in a one-on-one basis.Main resultsOne hundred ninety-one patients were recruited. Eighty patients (41.9%) had consulted other health-care professionals (HCP) for a second opinion after they were diagnosed to have cancer and 89 (46.6%) had utilized CAM. In multivariate analysis, late-stage disease (OR=2.65, 95% CI 1.26–5.58), treatment with radiotherapy (OR=2.27, 95% CI 1.19–4.33) and tertiary education (OR=11.28, 95% CI 3.06–41.54) were independent predictors for seeking a second opinion from other HCP and utilization of CAM. Patients who sought a second opinion from other HCP were more likely to utilize CAM (OR=6.12, 95% CI 3.24–11.54). Eighty percent of the patients did not inform their usual caregiver their utilization of CAM.ConclusionsSeeking a second opinion from other HCP is common in gynecologic cancer patients. Patients who seek a second opinion are more likely to utilize CAM.

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Hys Ngan

University of Hong Kong

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L.C. Wong

University of Hong Kong

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Y.M. Chan

University of Hong Kong

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Kar-Fai Tam

University of Hong Kong

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