Jessica Moline

Implementation of Universal Microsatellite Instability and Immunohistochemistry Screening for Diagnosing Lynch Syndrome in a Large Academic Medical Center

PURPOSE In 2009, the Evaluation of Genomic Applications in Practice and Prevention recommended that all colorectal cancers (CRCs) be screened for Lynch syndrome (LS) through microsatellite instability (MSI) or immunohistochemistry (IHC). No studies report how this process is implemented on a health system-wide basis. METHODS Since 2004, Cleveland Clinic has screened CRC specimens with MSI/IHC. Between January 2004 and July 2007, MSI/IHC results went only to the colorectal surgeon (approach 1). Between August 2007 and June 2008, colorectal surgeons and a genetic counselor received the MSI/IHC results, and the counselor e-mailed the colorectal surgeon regarding appropriate patients for genetic counseling (GC) referral (approach 2). After July 2008, the colorectal surgeon and counselor received MSI/IHC results, but the counselor contacted the patient to facilitate referral (approach 3). In approaches 2 and 3, patients were presumed to have sporadic CRC if the tumor lacked MLH1 expression and was also BRAF mutated or if the patient was diagnosed at age greater than 72 years and had no cancer family history. RESULTS Abnormal MSI/IHC results occurred in 178 (16%) of 1,108 patients. In approach 1, 21 (55%) of 38 patients with abnormal MSI/IHC were referred for GC, 12 (32%) of 38 underwent GC, and 10 (26%) of 38 underwent genetic testing (GT). In approach 2, nine (82%) of 11 patients were referred for GC, seven (64%) of 11 underwent GC, and five (45%) of 11 underwent GT. In approach 3, 56 (100%) of 56 patients were referred for GC, 40 (71%) of 56 underwent GC, and 37 (66%) of 56 underwent GT. Time from referral to GC was 10-fold quicker in approach 3 than approach 1. CONCLUSION Implementation of universal MSI/IHC with GC/GT, along with effective multidisciplinary communication and plans of responsibility for patient contact, resulted in increased identification of patients with LS.

Multiple endocrine neoplasia type 2: An overview

Multiple endocrine neoplasia type 2 is historically composed of three clinical subtypes, all of which are associated with germline mutations in the RET proto-oncogene. Multiple endocrine neoplasia type 2A, familial medullary thyroid carcinoma, and multiple endocrine neoplasia type 2B are collectively associated with a 70–100% risk of medullary thyroid carcinoma by age 70 years. Pheochromocytomas are identified in 50% of individuals with multiple endocrine neoplasia type 2A and multiple endocrine neoplasia type 2B. Furthermore, those with multiple endocrine neoplasia type 2A have a 20–30% risk for primary hyperparathyroidism. Individuals with multiple endocrine neoplasia type 2B often have distinct physical features including mucosal neuromas of the lips and tongue, medullated corneal nerve fibers, ganglioneuromatosis of the gastrointestinal tract, distinctive facies with enlarged lips, and a “Marfanoid” body habitus. Clinical recognition and accurate diagnosis of individuals and families who are at risk of harboring a germline RET mutation is critical for the prevention and management of potentially life-threatening neoplasms. This overview summarizes the clinical description of multiple endocrine neoplasia type 2, diagnosis and testing strategies, management and surveillance, and differential diagnosis for other related syndromes.

Implementation of tumor testing for lynch syndrome in endometrial cancers at a large academic medical center

OBJECTIVES Lynch syndrome (LS) is a hereditary condition that increases the risk for endometrial and other cancers. Recognizing women at risk for LS based on personal/family history is burdensome and imprecise. Tumor testing using microsatellite instability (MSI) testing and immunohistochemistry (IHC) for mismatch repair protein expression can be an effective strategy for identifying potential LS in patients presenting with colorectal or endometrial cancer. Here we describe our experience implementing a screening program for endometrial cancers. METHODS Endometrial cancers diagnosed ≤50 years or those with suspicious personal history or histopathologic features were screened with MSI/IHC, June 2009-June 2011. Criteria were later (July 2011-July 2012) expanded to patients diagnosed <60 years, or at any age with suspicious features, and finally (after August 2012) universal screening was implemented. Screening techniques began with both MSI and IHC for every tumor, and later converted to IHC for two proteins, and MLH1 promoter methylation analysis when indicated. A genetic counselor contacted patients directly to offer genetic counseling appointments. RESULTS Two hundred and forty-five endometrial cancers (average age, 57 years) were screened. Sixty-two patients (25%) had abnormal results, and 42 patients were referred for genetic counseling. Of the 42 patients, 34 underwent genetic counseling, 28 pursued genetic testing, and 11 were diagnosed with LS. When age and pathology criteria were used, 27 eligible cases were overlooked for screening and 3 cases of LS were found only because a clinician requested screening. CONCLUSIONS Universal screening of endometrial cancers for LS is practical and successfully implemented with collaboration among genetic counselors, gynecologic oncologists, and pathologists.

Pituitary Adenoma With Paraganglioma/Pheochromocytoma (3PAs) and Succinate Dehydrogenase Defects in Humans and Mice

CONTEXT Germline mutations in genes coding succinate dehydrogenase (SDH) subunits A, B, C, and D have been identified in familial paragangliomas (PGLs)/pheochromocytomas (PHEOs) and other tumors. We described a GH-secreting pituitary adenoma (PA) caused by SDHD mutation in a patient with familial PGLs. Additional patients with PAs and SDHx defects have since been reported. DESIGN We studied 168 patients with unselected sporadic PA and with the association of PAs, PGLs, and/or pheochromocytomas, a condition we named the 3P association (3PAs) for SDHx germline mutations. We also studied the pituitary gland and hormonal profile of Sdhb(+/-) mice and their wild-type littermates at different ages. RESULTS No SDHx mutations were detected among sporadic PA, whereas three of four familial cases were positive for a mutation (75%). Most of the SDHx-deficient PAs were either prolactinomas or somatotropinomas. Pituitaries of Sdhb(+/-) mice older than 12 months had an increased number mainly of prolactin-secreting cells and several ultrastructural abnormalities such as intranuclear inclusions, altered chromatin nuclear pattern, and abnormal mitochondria. Igf-1 levels of mutant mice tended to be higher across age groups, whereas Prl and Gh levels varied according to age and sex. CONCLUSION The present study confirms the existence of a new association that we termed 3PAs. It is due mostly to germline SDHx defects, although sporadic cases of 3PAs without SDHx defects also exist. Using Sdhb(+/-) mice, we provide evidence that pituitary hyperplasia in SDHx-deficient cells may be the initial abnormality in the cascade of events leading to PA formation.

Germline SDHx Variants Modify Breast and Thyroid Cancer Risks in Cowden and Cowden-like Syndrome via FAD/NAD-dependant Destabilization of p53

Cowden syndrome (CS), a Mendelian autosomal-dominant disorder, predisposes to breast, thyroid and other cancers. Germline mutations in phosphatase and tensin homolog (PTEN) have been recently reported in 23% of a large series of classic CS. Here, we validated our small (n = 10) pilot study in a large patient series that germline variations in succinate dehydrogenase genes (SDHx) occur in 8% (49/608) of PTEN mutation-negative CS and CS-like (CSL) individuals (SDHvar+). None of these SDHx variants was found in 700 population controls (P < 0.0001). We then found that SDHx variants also occur in 6% (26/444) of PTEN mutation-positive (PTENmut+) CS/CSL individuals (PTENmut+/SDHvar+). Of 22 PTENmut+/SDHvar+ females, 17 had breast cancers compared with 34/105 PTENmut+ (P < 0.001) or 27/47 SDHvar+ patients (P = 0.06). Notably, individuals with SDHvar+ alone had the highest thyroid cancer prevalence (24/47) compared with PTENmut+ patients (27/105, P = 0.002) or PTENmut+/SDHvar+ carriers (6/22, P = 0.038). Patient-derived SDHvar+ lymphoblastoid cells had elevated cellular reactive oxygen species, highest in PTENmut+/SDHvar+ cells, correlating with apoptosis resistance. SDHvar+ cells showed stabilized and hyperactivated hypoxia inducible factor (HIF)1α signaling. Most interestingly, we also observed the loss of steady-state p53 in the majority of SDHvar+ cells. This loss of p53 was regulated by MDM2-independent NADH quinone oxidoreductase 1-mediated protein degradation, likely due to the imbalance of flavin adenine dinucleotide/nicotinamide adenine dinucleotide in SDHvar+ cells. Our data suggest the potential regulation of HIF1α, p53 and PTEN signaling by mitochondrial metabolism in CS/CSL tumorigenesis. Together, our findings suggest the importance of considering SDHx as candidate predisposing and modifier genes for CS/CSL-related malignancy risks, and a mechanism which suggests ways of therapeutic reversal or prevention.

Prevalence of germline PTEN, BMPR1A, SMAD4, STK11, and ENG mutations in patients with moderate-load colorectal polyps

BACKGROUND & AIMS Gastrointestinal polyposis is a common clinical problem, yet there is no consensus on how to best manage patients with moderate-load polyposis. Identifying genetic features of this disorder could improve management and especially surveillance of these patients. We sought to determine the prevalence of hamartomatous polyposis-associated mutations in the susceptibility genes PTEN, BMPR1A, SMAD4, ENG, and STK11 in individuals with ≥5 gastrointestinal polyps, including at least 1 hamartomatous or hyperplastic/serrated polyp. METHODS We performed a prospective, referral-based study of 603 patients (median age: 51 years; range, 2-89 years) enrolled from June 2006 through January 2012. Genomic DNA was extracted from peripheral lymphocytes and analyzed for specific mutations and large rearrangements in PTEN, BMPR1A, SMAD4, and STK11, as well as mutations in ENG. Recursive partitioning analysis was used to determine cutoffs for continuous variables. The prevalence of mutations was compared using Fishers exact test. Logistic regression analyses were used to determine univariate and multivariate risk factors. RESULTS Of 603 patients, 119 (20%) had a personal history of colorectal cancer and most (n = 461 [76%]) had <30 polyps. Seventy-seven patients (13%) were found to have polyposis-associated mutations, including 11 in ENG (1.8%), 13 in PTEN (2.2%), 13 in STK11 (2.2%), 20 in BMPR1A (3.3%), and 21 in SMAD4 (3.5%). Univariate clinical predictors for risk of having these mutations included age at presentation younger than 40 years (19% vs 10%; P = .008), a polyp burden of ≥30 (19% vs 11%; P = .014), and male sex (16% vs 10%; P = .03). Patients who had ≥1 ganglioneuroma (29% vs 2%; P < .001) or presented with polyps of ≥3 histologic types (20% vs 2%; P = .003) were more likely to have germline mutations in PTEN. CONCLUSIONS Age younger than 40 years, male sex, and specific polyp histologies are significantly associated with risk of germline mutations in hamartomatous-polyposis associated genes. These associations could guide clinical decision making and further investigations.

Elevated plasma succinate in PTEN, SDHB, and SDHD mutation-positive individuals

Purpose:Cowden syndrome results from germline mutations in the gene for phosphatase and tensin homologue deleted on chromosome 10 (PTEN) and from variants in succinate dehydrogenase B and D subunits. We hypothesized that succinate accumulation may be common among individuals with SDH variants/mutations and those with PTEN mutations.Methods:Urine and blood were collected from individuals meeting full or partial Cowden syndrome diagnostic criteria or those with paraganglioma (PGL) or a known susceptibility paraganglioma-associated gene mutation, and succinate was measured. PTEN, SDHB, SDHC, and SDHD genes were sequenced from genomic DNA.Results:Elevated plasma succinate was observed in 13/21 (62%) individuals with germline PTEN, SDHB, or SDHD mutations as compared with 5/32 (16%) controls (P < 0.001), in 10/15 (67%) individuals with pathogenic PTEN mutations but in <20% of mutation-negative individuals meeting identical criteria, and in individuals with mutations in SDHB (1/1, 100%) and SDHD (2/5, 40%).Conclusion:Our data suggest that mutations in PTEN, SDHB, and SDHD reduce catalytic activity of succinate dehydrogenase, resulting in succinate accumulation, and identify a common biochemical alteration in these two patient populations (PTEN and SDHx mutation positive individuals). Plasma organic acid analysis may provide an effective and inexpensive screening method to determine when more expensive gene sequencing of PTEN and SDH genes is warranted.Genet Med 2012:14(6):616–619

Distinctive Phenotype in 9 Patients with Deletion of Chromosome 1q24-q25

Reports of individuals with deletions of 1q24 → q25 share common features of prenatal onset growth deficiency, microcephaly, small hands and feet, dysmorphic face and severe cognitive deficits. We report nine individuals with 1q24q25 deletions, who show distinctive features of a clinically recognizable 1q24q25 microdeletion syndrome: prenatal‐onset microcephaly and proportionate growth deficiency, severe cognitive disability, small hands and feet with distinctive brachydactyly, single transverse palmar flexion creases, fifth finger clinodactyly and distinctive facial features: upper eyelid fullness, small ears, short nose with bulbous nasal tip, tented upper lip, and micrognathia. Radiographs demonstrate disharmonic osseous maturation with markedly delayed bone age. Occasional features include cleft lip and/or palate, cryptorchidism, brain and spinal cord defects, and seizures. Using oligonucleotide‐based array comparative genomic hybridization, we defined the critical deletion region as 1.9 Mb at 1q24.3q25.1 (chr1: 170,135,865–172,099,327, hg18 coordinates), containing 13 genes and including CENPL, which encodes centromeric protein L, a protein essential for proper kinetochore function and mitotic progression. The growth deficiency in this syndrome is similar to what is seen in other types of primordial short stature with microcephaly, such as Majewski osteodysplastic primordial dwarfism, type II (MOPD2) and Seckel syndrome, which result from loss‐of‐function mutations in genes coding for centrosomal proteins. DNM3 is also in the deleted region and expressed in the brain, where it participates in the Shank–Homer complex and increases synaptic strength. Therefore, DNM3 is a candidate for the cognitive disability, and CENPL is a candidate for growth deficiency in this 1q24q25 microdeletion syndrome.

10 rare tumors that warrant a genetics referral.

The number of described cancer susceptibility syndromes continues to grow, as does our knowledge on how to manage these syndromes with the aim of early detection and cancer prevention. Oncologists now have greater responsibility to recognize patterns of cancer that warrant referral for a genetics consultation. While some patterns of common cancers are easy to recognize as related to hereditary cancer syndromes, there are a number of rare tumors that are highly associated with cancer syndromes yet are often overlooked given their infrequency. We present a review of ten rare tumors that are strongly associated with hereditary cancer predisposition syndromes: adrenocortical carcinoma, carcinoid tumors, diffuse gastric cancer, fallopian tube/primary peritoneal cancer, leiomyosarcoma, medullary thyroid cancer, paraganglioma/pheochromocytoma, renal cell carcinoma of chromophobe, hybrid oncocytoic, or oncocytoma histology, sebaceous carcinoma, and sex cord tumors with annular tubules. This review will serve as a guide for oncologists to assist in the recognition of rare tumors that warrant referral for a genetic consultation.

Pharmacogenetics of glutamate system genes and SSRI-associated sexual dysfunction

We examined whether polymorphisms in the GRIK2, GRIA3 and GRIA1 genes were associated with selective serotonin reuptake inhibitor (SSRI)-associated sexual dysfunction in 114 participants treated for depression. One polymorphism in GRIA1 (rs1994862) was associated with arousal dysfunction, providing further evidence for the role of GRIA1 in mechanisms underlying SSRI-associated sexual side effects.