The human genome contains many submicroscopic copy number variations which includes deletions, duplications and insertions. Although conventional karyotyping remains an important diagnostic tool in evaluating a dysmorphic patient with mental retardation, molecular diagnostic technology such as array comparative genomic hybridization (aCGH) has proven to be sensitive and reliable in detecting these submicroscopic anomalies. A 3 month-old infant with dysmorphic facies, microcephaly and global developmental delay was referred for genetic evaluation. Preliminary karyotyping which was confounded by the quality of metaphase spread was normal; however, aCGH detected a 30.6Mb deletion from 5p15.33-p13.3. This case illustrates the usefulness of aCGH as an adjunctive investigative tool for detecting chromosomal imbalances.
Cervical cancer is the second most common female malignancy in Malaysia. Despite advances in treatment, the overall survival for this disease has not changed in the last decade. Infection by certain types of HPV is recognized as a causal and necessary factor for its development. This study was carried out to determine the prevalence of HPV infection in abnormal cervical smears in Malaysian patients using archival cervical smears retrieved from the Cytopathology Unit, Universiti Kebangsaan Malaysia Medical Centre (UKMMC) between the years 1992-1995. DNA was extracted from 38 abnormal smears comprising 25 intraepithelial lesions and 13 cervical carcinomas and 10 normal smears. Amplification of HPV genes was carried out using the polymerase chain reaction (PCR) technique. HPV genotypes were determined using direct sequencing and the results were compared to the database from Genebank. DNA was successfully extracted from all 48 cervical smears. High-risk HPV (HR-HPV) genotypes were detected in 95% of the abnormal smears. Eight high-risk oncogenic types were identified: 16, 18, 31, 51, 52, 56, 58 and 66. All (100%) cervical cancer smears showed presence of HR-HPV compared to 92% of the cervical intraepithelial lesions. Among the eight HR-HPV genotypes identified, HPV 16 and 52 were the commonest (23.7% each) HPV genotypes encountered and among the CIN lesions, HPV 16 (28%) was the most frequent. We conclude that HPV 16 is the most prevalent HPV genotype present in abnormal cervical smears in Malaysian patients, and that the use of archival material to assess the presence of HPV is potentially worthwhile, and can be utilized for longitudinal studies of HPV presence and persistence.
Breast cancer is the commonest cancer affecting females in Malaysia, contributing 31% of all newly diagnosed cases amongst Malaysian women. The present retrospective cohort study evaluated the relationship between cerbB- 2 onco-protein overexpression with various tumour characteristics and survival rate of breast cancer patients treated at the Universiti Kebangsaan Malaysia Medical Centre (UKMMC) between 1996-2000. CerbB- 2 oncoprotein overexpression was determined by immunohistochemistry (IHC) and tumors showing 2+ positivity were verified by Fluorescence In Situ Hybridization (FISH). One hundred and seventy two patients were eligible for the study with a short-term follow-up (median) of 5.1 years. C-erbB-2 oncoprotein overexpression correlated with lymph node positivity, oestrogen receptor (ER) and progesterone receptor (PR) negativity. Univariate analyses showed shorter disease free survival (DFS) and overall survival (OS) in patients with cerbB- 2 oncoprotein overexpression, Malay ethnicity, higher tumour grade, lymph node positivity, ER and PR negativity. In a subgroup of patients with c-erbB-2 oncoprotein overexpression, a shorter OS was observed in those with lymph node positivity, ER and PR negativity. In multivariate prognostic analysis, lymph node status, ER status and tumour grading were the strongest independent prognostic factors for both OS and DFS. However, c-erbB-2 status was not a significantly independent prognostic factor, even in subsets with lymph node positive or negative group. C-erbB-2 oncoprotein overexpression correlated well with lymph node status, ER and PR. Shorter OS and DFS were significantly observed in patients with c-erbB-2 oncoprotein overexpression. Lymph node status, ER status and tumour grading were the only three independent prognostic factors for OS and DFS in this study. Although c-erbB-2 expression is obviously important from a biological standpoint, multivariate analysis showed that it is not an independent prognostic indicator in breast carcinoma in the local population.
At the present time, the differentiation between follicular thyroid carcinoma (FTC) and adenoma can be made only postoperatively and is based on the presence of capsular or vascular invasion. The ability to differentiate preoperatively between the malignant and benign forms of follicular thyroid tumors assumes greater importance in any clinical setting. The PAX8-PPARG translocation has been reported to occur in the majority of FTC. In this study, a group of 60 follicular thyroid neoplasms [18 FTC, 1 Hurthle cell carcinoma (HCC), 24 follicular thyroid adenomas (FTA), 5 Hurthle cell adenomas (HCA), and 12 follicular variants of papillary thyroid carcinomas (FV-PTC)] were analyzed to determine the prevalence of the PAX8-PPARG translocation by fluorescence in situ hybridization. The PAX8-PPARG translocation was detected in 2/18 FTC (11.1%). In addition, 2/18 (11.1%) FTC and 1/5 (20%) HCA showed 3p25 aneusomy only. The frequency of the translocation detected in the study was lower compared to the earlier studies conducted in Western countries. This might be attributed to the ethnic background and geographic location. Detection of either the PAX8-PPARG translocation or the 3p25 aneusomy in FTC indicates that these are independent genetic events. It is hereby concluded that 3p25 aneusomy or PAX8-PPARG translocation may play an important role in the molecular pathogenesis of follicular thyroid tumors.
The incidence of breast cancer has been on the rise in Malaysia. It is suggested that a subset of breast cancer cases were associated with germline mutation in breast cancer susceptibility (BRCA) genes. Most of the BRCA mutations reported in Malaysia were point mutations, small deletions and insertions. Here we report the first study of BRCA large genomic rearrangements (LGRs) in Malaysia. We aimed to detect the presence of LGRs in the BRCA genes of Malaysian patients with breast cancer.