Radiation in a New Era of Multiple Myeloma Management: Patterns of Utilization, Clinical, Radiologic, and Biochemical Outcomes, and Possible Genomic Correlates of Response

PURPOSE/OBJECTIVE(S)

Systemic therapies for multiple myeloma (MM) have advanced considerably, improving patient outcomes. Yet, the use of radiotherapy (RT) has remained heterogeneous, and even controversial, due to minimal data on outcomes. With the ultimate goal of guiding the design of prospective trials incorporating RT, we initiated a study of our institutional experience treating MM with RT since 1/1/2000. Here we report a preliminary feasibility analysis of an initial sample cohort, identifying patterns of RT utilization, outcomes, and impact of RT on radiographic and biochemical markers, with genomic characterization for more recently treated patients.

MATERIALS/METHODS

Five hundred six pathologically confirmed MM patients who received RT to 1190 sites between January 1, 2000, and June 1, 2022, were identified. Patient, disease, and treatment characteristics were analyzed for 50 consecutive patients treated in 2019 and tested for association with local and distant failure (LF, DF) using univariable and multivariable analysis. Genomic data was obtained via next generation sequencing using an institutional targeted sequencing panel.

RESULTS

Amongthe 50 patients analyzed (median 63 years), 90 lesions were treated with RT, 33% with concurrent systemic therapy, to median dose of 20 Gy (8-46 Gy) over a median of 5 fractions (1-25). RT Indications were pain (56%), critical structure involvement (25%), peri-operative (9%), salvage/consolidation (8%), and bridging therapy (2%). Median size of RT-treated lesions was 4.2 cm (1.4-7.9) and included non-vertebral bones (62%), spine (24%), and extramedullary sites (14%). The median number of lines of pre-RT therapy was 7 (1-14) and 51% had >9 lesions on imaging, 47% involving both medullary and extramedullary sites. With median follow-up of 12.4 months (0.5-46), LF occurred in 5% of treated sites and 89% had DF, most commonly in both medullary + extramedullary (51.4%) sites. Absolute decreases 1-week to 1-month post-RT were observed in % of marrow plasma cell (median 4.0%), M spike (0.30 g/dL), total protein (0.3 g/dL), K:L ratio (0.01), lesion size (1.5cm), and lesion SUV (3.1) but in this limited sample, none were significantly associated with disease control. A cohort of 62 RT-treated MM patients from 2016-2022 had genomic data available; most common tumor mutations were in TP53 (35%), HIST1 (34%), NRAS (34%), and KRAS (23%).

CONCLUSION

In this pilot analysis of a sampling cohort of RT-treated MM, we report on patterns of utilization, outcomes, and biochemical and radiographic correlates. At the meeting, we will present the full analysis of the >500 MM patients and further analyze emerging genomic data. We aim to characterize the role of RT in the modern era of systemic therapy to guide the design of future prospective trials and to inform novel approaches for incorporating RT into the treatment paradigm.

Lithium toxicity following Roux-en-Y gastric bypass: Mini review and illustrative case

Lithium is among the mainstays of treatment for bipolar disorder. Bariatric surgery can considerably change the oral bioavailability of drugs, particularly lithium. In this review, a 36-year-old male patient is described, who presented with lithium toxicity, including neurologic and gastric symptoms after undergoing Roux-en-Y gastric bypass. The mechanism of lithium toxicity is discussed; recommendations for clinicians regarding lithium use in postsurgical patients are provided; and previous case reports of lithium toxicity post-gastric bypass surgery are analyzed. Awareness and education of lithium absorption changes postbariatric surgery is essential for optimal patient care. Close clinical and drug concentration level monitoring is warranted.

Neurocysticercosis presenting as psychosis: A case report and a brief literature review

Patients with neurocysticercosis, a common infection of the central nervous system caused by Taenia solium, have been reported to develop neuropsychiatric complications. We report a unique case of recurrent psychosis caused by neurocysticercosis in a 37-year-old El Salvador immigrant woman and discuss the underlying pathophysiological mechanisms of the complications. We reviewed published case reports of neurocysticercosis that presented with psychotic features and compared their diagnostic evaluation, the underlying pathophysiology of complications and treatment regimen with our case. This review concludes that neurocysticercosis should be considered in the differential diagnosis of patients presenting with psychosis with a history of residence in an endemic area.

Social Media Reinvented: Can Social Media Help Tackle the Post-Pandemic Mental Health Onslaught?

Social media plays an omnipresent role in our modern lives, influencing every aspect of it, mental health being one of them. There has been increased focus on social media in recent times, especially its role in the ongoing coronavirus disease 2019 (COVID-19) pandemic. With various forms of social media, we hope to review the impact of various online platforms and emphasize their usage during the novel COVID-19 pandemic, which has led to a universal feeling of consternation throughout the world, mainly as a consequence of social distancing norms and cancellations of schools and places of work, which has affected not only the livelihood but also the way of life of scores of people.

Despite the negative press social media often receives in the field of mental health, there are opportunities to utilize its impact positively. This is not limited to connecting persons to mental health resources, spreading information about available COVID-19 treatment, and allowing social connection across the world. In this article, we review the renewed role that social media has had and future possibilities for its usage in the fight against the current pandemic.

Risk Factors for Postpartum Depression During COVID-19 Pandemic: A Systematic Literature Review

INTRODUCTION

The COVID-19 pandemic has had a devastating worldwide effect on mental health. Recent studies correlate the spreading of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with symptoms of depression, most prominent in postpartum women. Our systematic literature review scope is to identify the risk factors and predictors for postpartum depression (PPD) and describe the steps that should be taken to help postpartum women. This study will help clinicians, researchers, and policymakers to elucidate the predictors of PPD during this pandemic and prevent these adverse outcomes in future crises.

METHODS

We conducted a systematic search by employing databases PubMed, Google Scholar, Scopus, and Embase to identify articles published before March 2021. About 463 publications were generated during our search process and from those, 36 were reviewed, summarized, and synthesized. Studies qualified the criteria if they (1) utilized qualitative or quantitative design, (2) explored the risk factors for PPD, and (3) were written in English. Quality evaluation of each study was achieved by using criteria set by Lincoln and Guba.

RESULTS

Prevalence of depression symptoms ranged from 7% to 80.8% in postpartum women during the SARS-COV 2 pandemic. The risk factors for PPD were classified into 6 major categories: socio-demographic, psychological, pre-existing pathology, metabolic factors, previous events of miscarriage, and media misinformation.

CONCLUSION

It is extremely vital to care for women's mental health during pregnancy and after childbirth during these unprecedented times. This review urges the need to design adequate interventions for this vulnerable population to prevent negative consequences of PPD.

Lessons from a theory of change-driven evaluation of a global mental health funding portfolio

BACKGROUND

Given the underinvestment in global mental health to-date, it is important to consider how best to maximize the impact of existing investments. Theory of Change (ToC) is increasingly attracting the interest of funders seeking to evaluate their own impact. This is one of four papers investigating Grand Challenges Canada's (GCC's) first global mental health research funding portfolio (2012-2016) using a ToC-driven approach.

METHODS

A portfolio-level ToC map was developed through a collaborative process involving GCC grantees and other key stakeholders. Proposed ToC indicators were harmonised with GCC's pre-existing Results-based Management and Accountability Framework to produce a "Core Metrics Framework" of 23 indicators linked to 17 outcomes of the ToC map. For each indicator relevant to their project, the grantee was asked to set a target prior to the start of implementation, then report results at six-month intervals. We used the latest available dataset from all 56 projects in GCC's global mental health funding portfolio to produce a descriptive analysis of projects' characteristics and outcomes related to delivery.

RESULTS

12,999 people were trained to provide services, the majority of whom were lay or other non-specialist health workers. Most projects exceeded their training targets for capacity-building, except for those training lay health workers. Of the 321,933 people screened by GCC-funded projects, 162,915 received treatment. Most projects focused on more than one disorder and exceeded all their targets for screening, diagnosis and treatment. Fewer people than intended were screened for common mental disorders and epilepsy (60% and 54%, respectively), but many more were diagnosed and treated than originally proposed (148% and 174%, respectively). In contrast, the three projects that focused on perinatal depression exceeded screening and diagnosis targets, but only treated 43% of their intended target.

CONCLUSIONS

Under- or over-achievement of targets may reflect operational challenges such as high staff turnover, or challenges in setting appropriate targets, for example due to insufficient epidemiological evidence. Differences in delivery outcomes when disaggregated by disorder suggest that these challenges are not universal. We caution implementers, funders and evaluators from taking a one-size-fits all approach and make several recommendations for how to facilitate more in-depth, multi-method evaluation of impact using portfolio-level ToC.

Ectopic Intrathymic Parathyroid adenoma demonstrated on Tc-99m Sestamibi SPECT-CT

Intrathymic parathyroid adenoma is a rare cause of primary hyperparathyroidism. In this case, Tc-99m Sestamibi SPECT-CT successfully localized abnormal tracer uptake in the mediastinum with corresponding low density lesion on CT images suggestive of mediastinal parathyroid adenoma which late on confirmed on histopathology. After the median sternotomy a large intrathymic parathyroid adenoma was identified and excised. With the help of gamma probe the surgeons detect the lesion early and with more confidence as well as reducing the total operation time. Tc-99m Sestamibi SPECT-CT scintigraphy and gamma probe localization is recommended for preoperative and intra operative localization of ectopic parathyroid adenomas.

Gene signature combinations improve prognostic stratification of multiple myeloma patients

Multiple myeloma (MM) is a plasma cell neoplasm with significant molecular heterogeneity. Gene expression profiling (GEP) has contributed significantly to our understanding of the underlying biology and has led to several prognostic gene signatures. However, the best way to apply these GEP signatures in clinical practice is unclear. In this study, we investigated the integration of proven prognostic signatures for improved patient risk stratification. Three publicly available MM GEP data sets that encompass newly diagnosed as well as relapsed patients were analyzed using standardized estimation of nine prognostic MM signature indices and simulations of signature index combinations. Cox regression analysis was used to assess the performance of simulated combination indices. Taking the average of multiple GEP signature indices was a simple but highly effective way of integrating multiple GEP signatures. Furthermore, although adding more signatures in general improved performance substantially, we identified a core signature combination, EMC92+HZDCD, as the top-performing prognostic signature combination across all data sets. In this study, we provided a rationale for gene signature integration and a practical strategy to choose an optimal risk score estimation in the presence of multiple prognostic signatures.

111In-pentetreotide scintigraphy and 18F FDG PET-CT in differentiated thyroid carcinoma metastases with negative whole body radioiodine scan

Metastases of differentiated thyroid cancer (DTC) can lose affinity to radioiodine with the passage of time, with resultant difficulty in management. Thyroid tumors are known to express somatostatin receptors and therefore 111In-pentetreotide, somatostatin analogue, can visualize tumors with high concentration of somatostatin receptors. We report a case of I-131 whole body scan (WBS) negative recurrent metastatic papillary thyroid carcinoma with positive 18F FDG PET-CT and 111In-pentetreotide scan. Somatostatin receptor scintigraphy (SRS) with 111In-pentetreotide may be useful both in the staging and monitoring of patients with non-iodine avid carcinoma of the thyroid. 111In-pentetreotide scan positive patients are potential candidates for somatostatin receptor-targeted therapy.

New drugs and novel mechanisms of action in multiple myeloma in 2013: a report from the International Myeloma Working Group (IMWG)

Treatment in medical oncology is gradually shifting from the use of nonspecific chemotherapeutic agents toward an era of novel targeted therapy in which drugs and their combinations target specific aspects of the biology of tumor cells. Multiple myeloma (MM) has become one of the best examples in this regard, reflected in the identification of new pathogenic mechanisms, together with the development of novel drugs that are being explored from the preclinical setting to the early phases of clinical development. We review the biological rationale for the use of the most important new agents for treating MM and summarize their clinical activity in an increasingly busy field. First, we discuss data from already approved and active agents (including second- and third-generation proteasome inhibitors (PIs), immunomodulatory agents and alkylators). Next, we focus on agents with novel mechanisms of action, such as monoclonal antibodies (MoAbs), cell cycle-specific drugs, deacetylase inhibitors, agents acting on the unfolded protein response, signaling transduction pathway inhibitors and kinase inhibitors. Among this plethora of new agents or mechanisms, some are specially promising: anti-CD38 MoAb, such as daratumumab, are the first antibodies with clinical activity as single agents in MM. Moreover, the kinesin spindle protein inhibitor Arry-520 is effective in monotherapy as well as in combination with dexamethasone in heavily pretreated patients. Immunotherapy against MM is also being explored, and probably the most attractive example of this approach is the combination of the anti-CS1 MoAb elotuzumab with lenalidomide and dexamethasone, which has produced exciting results in the relapsed/refractory setting.

Patterns of second primary malignancy risk in multiple myeloma patients before and after the introduction of novel therapeutics

Recent studies have reported an increased risk of second primary malignancies (SPM) following multiple myeloma (MM) diagnosis associated with novel anti-myeloma treatments. We evaluated the risk of SPM among 36 491 MM cases reported to the Surveillance, Epidemiology, and End Results program (SEER) between 1973 and 2008. We calculated overall and site-specific standardized incidence ratio (SIR) and 95% confidence intervals (CI) for 2012 SPM cases diagnosed within the 35-year follow-up. There was no significant overall risk of SPM (SIR=0.98; 95% CI=0.94–1.02); however, there were multiple site-specific risk patterns. The risk of breast and prostate cancer was significantly decreased overall and across age, latency and the year of diagnosis strata. There was an ∼50% increased risk of colorectal cancer 5 years after MM diagnosis (P_trend<0.001). The risk of hematological malignancies was significantly increased, notably for acute myeloid leukemia (AML; SIR=6.51; 95% CI=5.42–7.83). There was a significant decreasing trend for AML over time, particularly for patients ⩾65. However, no significant change in risk was noted after the introduction of autologous stem cell transplant among younger patients (<65 years). On the basis of observed trends for overall SPM as well as AML, no association between the introduction of novel therapies and SPM following MM has emerged in this large population-based study.

Primary Non-Hodgkin Lymphoma of frontal sinus diagnosed by fine needle aspiration cytology

We present a rare case of primary non-Hodgkins Lymphoma of the frontal sinus diagnosed by Fine needle aspiration cytology (FNAC). FNAC is a safe, simple, rapid and effective technique that could be used to diagnose lesions even in unusual sites like paranasal sinuses with effective radiological guidance. Neoplasms of the frontal sinus could be easily misdiagnosed as an inflammatory process clinically. FNAC is a simple test to rule out a neoplasm. A review of a single case including radiographic, clinical, and pathologic findings was done, followed by a discussion on the pathological differential diagnosis highlighting relevant literature. Timely diagnosis is critical in the management of these cases.

KEYWORDS

Fine needle aspiration cytology, non-Hodgkin lymphoma, diffuse large B cell lymphoma, frontal sinus.

Plasma cell leukemia: consensus statement on diagnostic requirements, response criteria and treatment recommendations by the International Myeloma Working Group

Plasma cell leukemia (PCL) is a rare and aggressive variant of myeloma characterized by the presence of circulating plasma cells. It is classified as either primary PCL occurring at diagnosis or as secondary PCL in patients with relapsed/refractory myeloma. Primary PCL is a distinct clinic-pathological entity with different cytogenetic and molecular findings. The clinical course is aggressive with short remissions and survival duration. The diagnosis is based upon the percentage (≥ 20%) and absolute number (≥ 2 × 10(9)/l) of plasma cells in the peripheral blood. It is proposed that the thresholds for diagnosis be re-examined and consensus recommendations are made for diagnosis, as well as, response and progression criteria. Induction therapy needs to begin promptly and have high clinical activity leading to rapid disease control in an effort to minimize the risk of early death. Intensive chemotherapy regimens and bortezomib-based regimens are recommended followed by high-dose therapy with autologous stem cell transplantation if feasible. Allogeneic transplantation can be considered in younger patients. Prospective multicenter studies are required to provide revised definitions and better understanding of the pathogenesis of PCL.

Management of treatment-emergent peripheral neuropathy in multiple myeloma

Peripheral neuropathy (PN) is one of the most important complications of multiple myeloma (MM) treatment. PN can be caused by MM itself, either by the effects of the monoclonal protein or in the form of radiculopathy from direct compression, and particularly by certain therapies, including bortezomib, thalidomide, vinca alkaloids and cisplatin. Clinical evaluation has shown that up to 20% of MM patients have PN at diagnosis and as many as 75% may experience treatment-emergent PN during therapy. The incidence, symptoms, reversibility, predisposing factors and etiology of treatment-emergent PN vary among MM therapies, with PN incidence also affected by the dose, schedule and combinations of potentially neurotoxic agents. Effective management of treatment-emergent PN is critical to minimize the incidence and severity of this complication, while maintaining therapeutic efficacy. Herein, the state of knowledge regarding treatment-emergent PN in MM patients and current management practices are outlined, and recommendations regarding optimal strategies for PN management during MM treatment are provided. These strategies include early and regular monitoring with neurological evaluation, with dose modification and treatment discontinuation as indicated. Areas requiring further research include the development of MM-specific, patient-focused assessment tools, pharmacogenomic analysis of patient DNA, and trials to assess the efficacy of pharmacological interventions.

Renal insufficiency retains adverse prognostic implications despite renal function improvement following Total Therapy for newly diagnosed multiple myeloma

Renal insufficiency (RI) is a frequent complication of multiple myeloma (MM) with negative consequences for patient survival. The improved clinical outcome with successive Total Therapy (TT) protocols was limited to patients without RI. We therefore performed a retrospective analysis of overall survival, progression-free survival and time to progression (TTP) of patients enrolled in TT2 and TT3 in relationship to RI present at baseline and pre-transplant. Glomerular filtration rate was graded in four renal classes (RCs), RC1–RC4 (RC1 ⩾90 ml/min/1.73 m², RC2 60–89 ml/min/1.73 m², RC3 30–59 ml/min/1.73 m² and RC4 <30 ml/min/1.73 m²). RC1–3 had comparable clinical outcomes while RC4 was deleterious, even after improvement to better RC after transplant. Among the 85% of patients with gene expression profiling defined low-risk MM, Cox regression modeling of baseline and pre-transplant features, which also took into consideration RC improvement and MM complete response (CR), identified the presence of metaphase cytogenetic abnormalities and baseline RC4 as independent variables linked to inferior TTP post-transplant, while MM CR reduced the risk of progression and TTP by more than 60%. Failure to improve clinical outcomes despite RI improvement suggested MM-related causes. Although distinguishing RC4 from RC<4, 46 gene probes bore no apparent relationship to MM biology or survival.

Dynamic modeling of α-synuclein aggregation in dopaminergic neuronal system indicates points of neuroprotective intervention: experimental validation with implications for Parkinson's therapy

Protein aggregation is the major pathological hallmark seen in neurodegenerative disorders such as Parkinson's disease (PD). Alpha-synuclein (αS) is the main component of protein aggregates that form Lewy bodies (LBs) in PD and dementia with LBs. There have been several attempts to intervene in the process of expression, modification, clearance, and aggregation of αS as a therapeutic strategy toward neuroprotection. In this study, we have employed a novel, predictive, system level approach in silico to study four different strategies of anti-aggregation therapies: (a) reduction in αS modifications such as phosphorylation, nitration, or truncation in an approach called "seed clearance;" (b) "anti-oligomerization" approach through blocking the early oligomers formation; (c) "oligomers clearance" process by increasing its lysosomal degradation; and (d) "anti-aggregation" that involves prevention of aggregate formation at a later stage. These strategies were tested in a virtual dopaminergic neuronal system triggered by overexpression (OE) of mutant αS-A53T with or without rotenone (Rot)-induced oxidative stress. The results were compared by analyzing markers related to various end points such as oxidative stress, dopamine (DA) metabolism, proteasome function, survival and apoptosis. The experimental system and anti-oligomerization strategies were recapitulated in vitro in M17 dopaminergic cells overexpressing mutant αS-A53T triggered with Cu(II)-mediated oxidative stress, and the experimental data prospectively corroborated with the predictive results. Through this analysis, we found that intervention in the early part of the aggregation pathway by prevention of oligomer formation and increased clearance is indeed a good neuroprotective strategy, whereas anti-aggregation efforts to break up the aggregate at later stages has negative effects on the system.

Extensive visceral calcification demonstrated on Tc-99m MDP bone scan in patient with sphenoidal sinus carcinoma and hypercalcaemia of malignancy: a bad prognostic sign

Sphenoidal sinus carcinoma is a rare cause of hypercalcemia of malignancy. We report on a 37-year-old male with sphenoidal sinus carcinoma with intracranial extension who developed hypercalcemia of malignancy with progressing disease and demonstrated diffuse metastatic visceral calcifications of lungs, myocardium, stomach, kidneys and thyroid on follow-up 99mTc-methylene diphosphonate bone scan. In the absence of extensive skeletal metastases, bone scan help confirm humoral nature of hypercalcaeimia.

Scintimammography in conjunction with ultrasonography for local breast cancer recurrence in post-mastectomy breast

The aim of this study was to compare the usefulness of (99)Tc(m)-methoxy-isobutyl-isonitrile (MIBI) scintimammography and ultrasonography, alone and in combination, for the detection of chest wall recurrence in the post-mastectomy breast. A total of 41 consecutive post-mastectomy patients (mean age 46.6 years; median age 45 years) with clinical suspicion of breast cancer recurrence were evaluated. For scintimammography all patients received a 740-900 MBq iv injection of (99)Tc(m)-MIBI; planar images were taken 5-10 min post-injection followed by supine single photon emission CT. Breast ultrasonography was performed in each patient using a 7.5 MHz transducer. Both MIBI uptake and ultrasound findings were documented using standard protocols. All patients had fine needle aspiration cytology biopsy (FNAC), core biopsy or excision biopsy for final tissue diagnosis. Of the 41 patients, 24 had true positive signs of local breast cancer recurrence upon ultrasonography, 10 were diagnosed as true negatives, a sensitivity of 86%, specificity 77%, positive predictive value (PPV) 89%, negative predictive value (NPV) 71% and accuracy 83% (p = 0.001). By comparison, scintimammography findings were found to be true positive in 25 patients and true negative in 12 patients - sensitivity 89%, specificity 92%, PPV 96%, NPV 80% and accuracy 90% (p = 0.001). Using a combination of these two modalities, the combined sensitivity was 100%, specificity 77%, PPV 90%, NPV 100% and accuracy 93%. The high NPV of the two studies in combination implies a potential use of this approach to exclude recurrent disease in patients with a low initial index of suspicion and/or when histology is indeterminate.

Functional breast imaging with Tc 99m Mibi for detection of primary breast lesion and axillary lymph node metastases

Breast cancer is the most common cancer among women and the second leading cause of death in women after lung cancer. The principle aim is to study the utility of Tc- MIBI scintimammography in evaluation of breast cancer and lymph node metastases.

MATERIALS AND METHODS

A total of 36 patients both with breast lumps or/and axillary masses suspected breast cancer on clinical examination and/or at conventional imaging procedures (CIP's) were included in this study. The mean age was 47.13 years, median age 47 and age range 22-77 years. All patients received a 740-1000 MBq bolus IV injection of 99mTc-MIBI preferably in a pedal vein. At 5-10 min post injection planar images were obtained in prone lateral and supine anterior position using dual head gamma camera. MIBI uptake was scored as follows: 1 for normal uptake (compared with contralateral side), 2 for focal low intense uptake (equivocal), 3 for focal high intense uptake (positive). All patients had histopathology for tissue diagnosis.

RESULTS

There were 36 patients who presented with breast lesions (30 palpable, 6 non-palpable) and 8 patients with axillary lump. Scan was found true positive in 24 patients and was true negative in 7 patients with breast lesion. In case of axillary lump, it was true positive in 4 and true negative in 2 patients. Planar scintimammography showed sensitivity of 86%, specificity 88%, PPV 96%, NPV 64% and accuracy of 86% (p<0.01). However sensitivity, specificity, PPV, NPV and accuracy for axially metastasis were 86%, 67%, 80%, 67% and 75% respectively. (P-value <0.01).

CONCLUSION

It is concluded from the study that SMM has good diagnostic accuracy in the detection of breast cancer specially in palpable lesion and lymph node metastases.

Population structure of the Southeast Asian river catfish Mystus nemurus

A total of 143 microsatellites were isolated from Mystus nemurus using a 5' anchored polymerase chain reaction technique or the random amplified hybridization microsatellite method, the first set of microsatellite markers developed for the Southeast Asian river catfish. Twenty polymorphic microsatellite loci were used as markers for population characterization of M. nemurus from six different geographical locations in Malaysia (Perak, Kedah, Johor, UPM, Sarawak and Terengganu). The number of alleles per locus ranged from 2 to 11 with 6.3 as the average number of alleles per locus. Characterization of the populations showed relatively high levels of genetic variation compared with previous studies using allozyme markers. The highest genetic similarity was found between Perak and Kedah, while the highest genetic distance was found between Terengganu and Kedah. The majority of clustering was in accordance with geographical locations and the histories of the populations. Microsatellite analysis indicated that the Sarawak population might be genetically closer to the Peninsular Malaysian populations than has been previously shown by other molecular marker studies.