MicroRNA (miRNA) expression profiling of peripheral blood samples in multiple myeloma patients using microarray

MicroRNAs (miRNAs) are mostly located at cancer-associated genomic regions or in fragile sites, suggesting their important role in the pathogenesis of human cancers. Multiple myeloma (MM) is a cancer of plasma cells, the third most common cancer of the blood after lymphoma and leukaemia. There are several published reports on miRNAs in MM, however most used bone marrow rather than peripheral blood samples. The aim of this study is to characterise miRNA expression in normal and MM patients using peripheral blood samples as it is less invasive and is readily available from patients. Blood samples from 35 MM patients were analysed using the microarray method. We identified up-regulation of 36 miRNAs (57%) and down-regulation of 27 miRNAs (43%). We also identified the CCND2, HMGA2 and IGF1R genes were among the highly predictive target genes (P(CT) > 0.80) for most of the deregulated miRNAs. These genes are known to play important roles in MM as well as other cancers. Five miRNAs (let-7c, miR-16, miR- 449, miR-181a and miR-181b) were found to exhibit similar expression patterns (p < 0.05) in peripheral blood when compared to data obtained by using bone marrow aspirates from MM patients in other studies. In conclusion, our study has demonstrated that miRNAs are also present and differentially expressed in the peripheral blood of MM patients compared to controls and may potentially serve as candidate tumour biomarkers in MM. In particular, let-7c and miR-16 have been shown to be significantly expressed in the bone marrow.

3p25 Aneusomy in Follicular Thyroid Neoplasms: A Report of Three Cases with Review of Literature

Aneusomy is an early genetic event and a characteristic feature of many solid tumors. It is often associated with poor prognosis in cancer patients. The involvement of PAX8-PPARγ rearrangement in tumorigenesis of follicular thyroid lesions has been widely assessed. However, there were few reports on aneusomy of the PPARγ gene at the 3p25 locus in follicular thyroid lesions. It remains undetermined whether these abnormalities can be translated into improved diagnosis, classification, or outcome prediction. Herein, we report three cases of follicular thyroid neoplasms [two follicular thyroid carcinomas (FTCs) and one Hurthle cell adenoma (HCA)] with 3p25 aneusomy detected by fluorescence in situ hybridization (FISH). 3p25 trisomy was observed in one FTC and one HCA while 3p25 tetrasomy was observed in one FTC. Furthermore, all three lesions did not show overexpression of PPARγ protein. Hurthle cell neoplasms (HCN) are distinct clinically and histologically from other follicular thyroid neoplasms (FTN). However, the presence of the aneusomy in HCA and FTC indicates that there could be a biological continuum between the two and chromosomal gains might play an important role in the pathogenesis of these two types of neoplasms. Despite their differences, HCN and FTN may share the same early genetic event in tumour development.

Sybr Green Real-Time PCR is a Useful Method in Screening for High Risk Human Papilloma Virus Types 16 and 18 in Neoplastic Cervical Cancer

Human papillomavirus (HPV) plays an important role in the pathogenesis of cervical cancer. HPV has been found in 99.7% of cervical cancers worldwide. In Malaysia, it is the second most common cancer among women in all major ethnic groups. The main purpose of this study was to establish the method of SyBrGreen Real-Time PCR and apply it for identification of multiple infections of the two high risk HPV subtypes. In this study, 57 positive samples for HPV 16 and HPV 18 were used to establish a simple and sensitive method to detect and identify HPV infection in the cervical neoplasia at different stages of the disease by using real-time ABICycler SyBrGreen 1 technology. The results showed 67 HPV genomes in 57 samples. HPV 16 genome was detected in 55/67 (82%) cases while HPV 18 was detected in 8/67 (12%) cases with 4 cases showing multiple infections of HPV 16 and HPV 18. HPV 16 was the most prevalent followed by HPV 18. Using SyBr Green Real-Time PCR techniques, the results showed that DNA melting curve for HPV 16 had a peak around 80.2ºC and Ct value of 20 cycles whereas the DNA melting curve for HPV 18 around 79.2ºC and Ct INTRODUCTION value of 22 cycles. In conclusion, a SyBr Green Real-Time PCR method has the potential for clinical usage in detection and identification of HPV infection in cervical neoplasia at different stages of the disease.

Elevated Expression of CD151 Gene in Estrogen Receptor and Progesterone Receptor Positive Breast Carcinoma

The tetraspanin gene, CD151 is involved in various tumour cell progression and metastasis. Its expression is increased in high grade, estrogen receptor negative and c-erbB-2 positive breast cancer. However, the biological function and expression phenotype among different tumour status, estrogen receptor (ER) status, progesterone receptor (PR) status and c-erbB-2 expression in multi-ethnic Malaysian breast cancer patients has not been well investigated. We used quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) to measure the CD151 gene expression in 45 breast cancers. Our preliminary results revealed that CD151 expression is significantly higher in ER positive and PR positive breast cancers at 95% and 99% confidence intervals, respectively. In contrast, there is no significant correlation between CD151 expression and tumour grades or c-erbB-2 status at 95% confidence interval level. Our preliminary findings suggested that CD151 may be involved in the estrogen responsive pathways. CD151 could be a potential prognostic marker and therapeutic target in the treatment of estrogen dependent breast cancer patients.

Cri-du-chat Syndrome: Application of Array CGH in Diagnostic Evaluation

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.

Concomitant t(8;21) and Trisomy 4 in a Patient with Acute Myeloid Leukemia (AML)

The t(8;21)(q22;q22) is a frequently occurring aberration in acute myeloid leukemia (AML) (18-20%) and usually correlate with French-America-British (FAB) M2 subtype. Several studies showed that patients carrying this abnormality demonstrated good response to standard chemotherapy but also have a high incidence of disease relapse. Trisomy 4 is a rare and specific chromosomal abnormality occurring in AML M2 or M4 of the FAB subtypes. We report a case of a 33-year-old female with an apparently clinical and hematologic diagnosis of acute promyelocytic leukemia (APL) in whom cytogenetic analysis revealed an abnormal karyotype with trisomy 4, in addition to t(8;21). Trisomy 4 and t(8;21) in a patient with AML is rare. The significance of t(8;21) with trisomy 4 in AML are unclear but patients bearing this abnormality are associated with a poor prognosis.