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PMS2, a Lynch Syndrome gene, presents challenges in genetic testing due to the existence of multiple pseudogenes. This study aims to describe a series of cases harboring a variant in the PMS2CL pseudogene that has been incorrectly assigned to PMS2 with different nomenclatures. We reviewed data from 647 Brazilian patients who underwent multigene genetic testing at a single center to identify those harboring the PMS2 V1:c.2186_2187delTC or V2:c.2182_2184delACTinsG variants, allegedly located at PMS2 exon 13. Gene-specific PCR and transcript sequencing was performed. Among the 647 individuals, 1.8% (12) carried the investigated variants, with variant allele frequencies ranging from 15 to 34%. By visually inspecting the alignments, we confirmed that both V1 and V2 represented the same variant and through gene-specific PCR and PMS2 transcript analysis, we demonstrated that V1/V2 is actually located in the PMS2CL pseudogene. Genomic databases (ExAC and gnomAD) report an incidence of 2.5 - 5.3% of this variant in the African population. Currently, V1 is classified as "uncertain significance" and V2 as "conflicting" in ClinVar, with several laboratories classifying them as "pathogenic". We identified a frequent African PMS2CL variant in the Brazilian population that is misclassified as a PMS2 variant. It is likely that V1/V2 have been erroneously assigned to PMS2 in several manuscripts and by clinical laboratories, underscoring a disparity-induced matter. Considering the limitations of short-read NGS differentiating between certain regions of PMS2 and PMS2CL, using complementary methodologies is imperative to provide an accurate diagnosis., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Background: Triple-negative breast cancer (TNBC) is the neoplasia most associated with BRCA1 germline pathogenic variants (PV) and is more likely to develop metastases than the other breast cancer (BC) subtypes, mainly in the lungs and the central nervous system (CNS). Recently, BRCA2 carriers were shown to have a higher risk for developing CNS metastases. However, the patterns of recurrence and metastases of BRCA2 carriers with TNBC are unknown., Methods: TNBC patient data attending the A.C. Camargo Cancer Center, from 1998 through 2020, were verified either by medical records or by BRCA1/2 genetic testing carried out. Multivariable logistic regression models were fit to the data to assess the independent factors for bone and CNS metastases. Adjustment was done using all independent variables with p < 0.2 in the univariable Cox model to describe the relationship between the independent variables until time of death., Results: A total of 388 TNBC patients were evaluated. We identified PV in BRCA1/2 genes in 21% (82/388), being 17.7% (69/388) in BRCA1 and only 3.3% (13/388) in BRCA2. A total of 120 patients (31%) developed distant metastases. Bone or CNS metastases were observed in 40% and 60% of BRCA2 PV carriers (p = 0.155), respectively. The BRCA2 carriers tended to have a higher likelihood of developing bone metastases (OR, 4.06; 95% CI, 0.82-20.01; p = 0.085), when compared to BRCA1 carriers (OR, 0.6; 95% CI, 0.12-2.87; p = 0.528). BRCA2 carriers had an OR of 1.75 (95% CI, 0.33-9.14; p = 0.503) for CNS metastasis development, while BRCA1 carriers had an OR of 0.72 (95% CI, 0.23-2.23; p = 0.574)., Conclusions: Patients with TNBC and PV in the BRCA2 gene had higher frequencies of secondary bone involvement and CNS in the course of the disease. However, the BRCA2 PV did not represent an independent outcome predictor of metastases and overall survival. Efforts to increase the number of BRCA2 carriers among TNBC patients are crucial for determining their risk of developing bone and CNS metastases compared to BRCA2 noncarriers., (© 2023 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

My parents taught me the value of a good education. My studies at the state universities of Michigan and Colorado and postgraduate studies at the University of Utrecht built on an interest in astronomy that dated back to high school. These institutions enabled me to have a rewarding fifty-year career focused on the physics of the Sun. My work combined research and education at the High Altitude Observatory, the University of Utrecht, the Sacramento Peak Observatory, the University of California San Diego, the University of Hawaii, and Montana State University. My professional interests ranged from spectroscopic diagnostics and radiative transfer, especially of the flaring solar chromosphere, to the helicity of magnetic fields of active regions in the chromosphere, corona, and interplanetary medium, part of what is now called heliophysics and space weather. I am honored to have been recognized for my efforts as a scientific leader, mentor, and teacher. I am lucky to have lived at a time when access to space led the field of solar physics to grow dramatically, including global studies of solar activity, the heliosphere, and space weather., Competing Interests: Disclosure of Potential Conflicts of InterestThe author declares to have no conflicts of interest., (© The Author(s), under exclusive licence to Springer Nature B.V. 2022.)

The majority of the hereditary triple-negative breast cancers (TNBCs) are associated with BRCA1 germline mutations. Nevertheless, the understanding of the role of BRCA1 deficiency in the TNBC tumorigenesis is poor. In this sense, we performed whole-exome sequencing of triplet samples (leucocyte, tumor, and normal-adjacent breast tissue) for 10 cases of early-onset TNBC, including 5 hereditary (with BRCA1 germline pathogenic mutation) and 5 sporadic (with no BRCA1 or BRCA2 germline pathogenic mutations), for assessing the somatic mutation repertoire. Protein-affecting somatic mutations were identified for both mammary tissues, and Ingenuity Pathway Analysis was used to investigate gene interactions. BRCA1 and RAD51C somatic promoter methylation in tumor samples was also investigated by bisulfite sequencing. Sporadic tumors had higher proportion of driver mutations (≥25% allele frequency) than BRCA1 hereditary tumors, whereas no difference was detected in the normal breast samples. Distinct gene networks were obtained from the driver genes in each group. The Cancer Genome Atlas data analysis of TNBC classified as hereditary and sporadic reinforced our findings. The data presented here indicate that in the absence of BRCA1 germline mutations, a higher number of driver mutations are required for tumor development and that different defective processes are operating in the tumorigenesis of hereditary and sporadic TNBC in young women., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

The detection of germline mutations in BRCA1 and BRCA2 is essential to the formulation of clinical management strategies, and in Brazil, there is limited access to these services, mainly due to the costs/availability of genetic testing. Aiming at the identification of recurrent mutations that could be included in a low-cost mutation panel, used as a first screening approach, we compiled the testing reports of 649 probands with pathogenic/likely pathogenic variants referred to 28 public and private health care centers distributed across 11 Brazilian States. Overall, 126 and 103 distinct mutations were identified in BRCA1 and BRCA2, respectively. Twenty-six novel variants were reported from both genes, and BRCA2 showed higher mutational heterogeneity. Some recurrent mutations were reported exclusively in certain geographic regions, suggesting a founder effect. Our findings confirm that there is significant molecular heterogeneity in these genes among Brazilian carriers, while also suggesting that this heterogeneity precludes the use of screening protocols that include recurrent mutation testing only. This is the first study to show that profiles of recurrent mutations may be unique to different Brazilian regions. These data should be explored in larger regional cohorts to determine if screening with a panel of recurrent mutations would be effective.

Purpose: BRCA1 germline mutation is closely associated with triple-negative breast cancer. BRCA deficiency leads to impaired DNA repair and tumor development, and understanding this deficiency, in both hereditary and sporadic scenarios, is of great clinical and biological interest. Here, we investigated germline or somatic events that might lead to BRCA1 impairment in triple-negative breast cancer. We also analyzed the clinical implications associated with BRCA deficiency., Methods: Next-generation sequencing for the BRCA1/2 genes and multiplex ligation-dependent probe amplification (MLPA) for the BRCA1 gene were performed for mutation screening. A customized bisulfite next-generation sequencing approach was used for assessing BRCA1 promoter methylation status in tumor tissue., Results: A total of 131 triple-negative cases were assessed, and germline pathogenic variants were detected in 13.0% of all cases and in 26% of cases diagnosed in young women. Most germline pathogenic variants (88.2%) occurred in the BRCA1 gene. BRCA1 promoter hypermethylation was detected in 20.6% of tumors; none of these tumors were in BRCA1/2 pathogenic variant carriers. BRCA1 impairment by either germline or somatic events was significantly more frequent in young women (55% in those ≤ 40 years; 33% in those 41-50 years; 22% in those > 50 years of age) and associated with better overall and disease-free survival rates in this group of patients., Conclusions: BRCA1 deficiency was recurrent in early-onset triple-negative breast cancer in Brazilian patients and associated with improved survival. With the new treatment modalities being investigated, including poly (ADP-ribose)-polymerase (PARP) inhibitor therapy, our results suggest that a significant proportion of young women with this subtype of tumor might benefit from PARP inhibitor treatment, which warrants further investigation.

Despite remarkable advances in diagnosis, prognosis and treatment, advanced or recurrent breast tumors have limited therapeutic approaches. Many treatment strategies try to explore the limitations of DNA damage response (DDR) in tumor cells to selectively eliminate them. BRCT (BRCA1 C-terminal) domains are present in a superfamily of proteins involved in cell cycle checkpoints and the DDR. Tandem BRCT domains (tBRCT) represent a distinct class of these domains. We investigated the expression profile of 7 tBRCT genes (BARD1, BRCA1, LIG4, ECT2, MDC1, PAXIP1/PTIP and TP53BP1) in breast cancer specimens and observed a high correlation between PAXIP1 and TP53BP1 gene expression in tumor samples. Tumors with worse prognosis (tumor grade 3 and triple negative) showed reduced expression of tBRCT genes, notably, PAXIP1 and TP53BP1. Survival analyses data indicated that tumor status of both genes may impact prognosis. PAXIP1 and 53BP1 protein levels followed gene expression results, i.e., are intrinsically correlated, and also reduced in more advanced tumors. Evaluation of both genes in triple negative breast tumor samples which were characterized for their BRCA1 status showed that PAXIP1 is overexpressed in BRCA1 mutant tumors. Taken together our findings indicate that PAXIP1 status correlates with breast cancer staging, in a manner similar to what has been characterized for TP53BP1.

Background: Hereditary breast and ovarian cancer is characterized by mutations in BRCA1 or BRCA2 genes and PCR-based screening techniques, such as capillary sequencing and next-generation sequencing (NGS), are considered gold standard methods for detection of pathogenic mutations in these genes. Single-nucleotide polymorphisms (SNPs) constitute a vast source of variation in the human genome and represent a risk for misdiagnosis in genetic testing, since the presence of a SNP in primer-annealing sites may cause false negative results due to allele dropout. However, few reports are available and the frequency of this phenomenon in diagnostic assays remains unknown., Methods and Results: In this article, we investigated the causes of a false negative capillary sequencing result in BRCA1 involving a mother-daughter dyad. Using several molecular strategies, including different DNA polymerases, primer redesign, allele-specific PCR and NGS, we established that the initial misdiagnosis was caused by a SNP located in the primer-annealing region, leading to allele dropout of the mutated allele., Conclusion: Assuming that this problem can also occur in any PCR-based method that are widely used in diagnostic settings, the clinical report presented here draws attention for one of the limitations of genetic testing in general, for which medical and laboratory communities need to be aware.

Lynch syndrome (LS) accounts for 3-5% of all colorectal cancers (CRC) and is inherited in an autosomal dominant fashion. This syndrome is characterized by early CRC onset, high incidence of tumors in the ascending colon, excess of synchronous/metachronous tumors and extra-colonic tumors. Nowadays, LS is regarded of patients who carry deleterious germline mutations in one of the five mismatch repair genes (MMR), mostly in MLH1 and MSH2, but also in MSH6, PMS1 and PMS2. To comprehensively characterize 116 Brazilian patients suspected for LS, we assessed the frequency of germline mutations in the three minor genes MSH6, PMS1 and PMS2 in 82 patients negative for point mutations in MLH1 and MSH2. We also assessed large genomic rearrangements by MLPA for detecting copy number variations (CNVs) in MLH1, MSH2 and MSH6 generating a broad characterization of MMR genes. The complete analysis of the five MMR genes revealed 45 carriers of pathogenic mutations, including 25 in MSH2, 15 in MLH1, four in MSH6 and one in PMS2. Eleven novel pathogenic mutations (6 in MSH2, 4 in MSH6 and one in PMS2), and 11 variants of unknown significance (VUS) were found. Mutations in the MLH1 and MSH2 genes represented 89% of all mutations (40/45), whereas the three MMR genes (MSH6, PMS1 and PMS2) accounted for 11% (5/45). We also investigated the MLH1 p.Leu676Pro VUS located in the PMS2 interaction domain and our results revealed that this variant displayed no defective function in terms of cellular location and heterodimer interaction. Additionally, we assessed the tumor phenotype of a subset of patients and also the frequency of CRC and extra-colonic tumors in 2,365 individuals of the 116 families, generating the first comprehensive portrait of the genetic and clinical aspects of patients suspected of LS in a Brazilian cohort.

Individual premolar teeth of 22 normal volunteers were stimulated via intradentinal electrodes using brief electrical pulses. Questionnaires were used to determine the qualities of sensations produced by this stimulation. Operationally defined 'innocuous' sensations predominated between 1 and 10 dB SL, and were absent above 30 dB SL. Similarly defined 'painful' sensations were observed throughout the range of suprathreshold intensities but were most common above 20 dB SL. These findings demonstrate that non-painful sensations can arise from electrical tooth pulp excitation in circumstances in which spread of the stimulating current to periodontal and gingival structures is most unlikely. Two interpretations of these results are considered: (1) that tooth pulp afferents may have some unspecified sensory function besides mediation of painful sensations and (2) that they may be specialized in the mediation of nociceptive impulses but may give rise to innocuous sensations under special circumstances.

Brief electrical pulses were applied to the pulp of individual pre-molar teeth of 14 healthy, adult volunteers via wire electrodes implanted and sealed in dentine. The sensation threshold was estimated in each individual by the Two-Alternative Forced-Choice Staircase (2AFCS) method. Seven, 5 or 4 stimulus intensities were employed which were equally spaced in a logarithmic scale between 10 microA above threshold and 500 microA. Magnitude estimates of the subjective intensity of the sensation produced by individual dental excitations were obtained. Cerebral tooth pulp-evoked potentials were simultaneously recorded in 11 subjects. The growth of psychological sensory magnitude with increasing strength of electrical stimulus conformed to the general psychophysical power law. Individual power function exponents varied from 0.204 to 0.907 with a mean of 0.475 and a standard deviation of 0.190. The amplitude of TPEPs, measured between components N135 and P293, also was a power function of stimulus intensity. The exponents of individual TPEP amplitude-intensity functions ranged from 0.055 to 0.362 with a mean of 0.144 and a standard deviation of 0.100. These last exponents were substantially smaller than those describing the growth of psychological magnitude estimates. Neither magnitude estimation nor TPEP amplitude-intensity functions displayed abrupt changes in slope which might accompany transition from one operating sensory mechanism to another and/or changes in qualities of subjective sensations from 'innocuous' to 'uncomfortable' to 'painful.' The result of our psychophysical and electrophysiologic experiments indicate that: (1) albeit highly specialized both morphologically and functionally, human tooth pulp has certain fundamental properties in common with other sensory systems and (2) late midline TPEP components may provide measures of central events that, within a range of stimulus intensities, are associated with the perception of pain, but should not be looked upon as specific indicators of pain processes.

Horseradish peroxidase (HRP) was implanted in one maxillary canine of cats and the transganglionic transport to the brain stem studied and mapped. HRP-positive fibers and terminal granules are distributed ipsilaterally to each subdivision of the trigeminal complex but are heaviest in the main sensory nucleus, adjacent pars oralis and pars interpolaris near obex with somewhat less in the rest of pars oralis and least in pars caudalis. The distribution indicates a wider central representation than previous anatomical reports and corresponds well with certain physiological studies.

Toxic ricin was used to study the central distribution of dental afferents in the cat. Following intrapulpal ricin injections ganglion cell degeneration is seen in the II and III ganglion divisions. Central argyrophilic degeneration occurs in the dorsal portion of all ipsilateral trigeminal nuclei. Ventral degeneration is seen in the pars interpolaris and pars caudalis. No contralateral degeneration was observed. The results are discussed with regard to previous studies of the central location of dental afferents.

Electron microscopy is used to study changes in the axons and terminals in the cat brain stem trigeminal nuclei, main sensory, and partes interpolaris and caudalis, during the process of natural tooth shedding. Areas previously showing light optical argyrophilic degeneration products and adjacent areas lacking this degeneration are included. Various types of alteration occur early during tooth loss, including increased presumed glycogen, increased cytoplasmic density, flocculence, lucency, and neurofilamentous hyperplasia. By the stage of maximum exfoliation, terminals and axons of marked density become prominent in areas showing argyrophilia, whereas nondense forms occur elsewhere. By late eruption ages, all forms of degenerated terminals and axons are rare, but phagocytes are heavily laden with similar forms of debris. The sequence of ultrastructural events is discussed in light of recent studies of transganglionic degeneration, their correlation with light microscopic findings, and the potential implications for central plasticity in this system.

The pulp of individual teeth of 17 normal adult volunteers was electrically stimulated via pairs of electrodes implanted into dentine. Computer-summated responses recorded from the surface of the head were composed of two concurrent sequences of events, one of which was seen maximally over midline areas and the other over the lower portions of the postcentral regions. Appropriate tests demonstrated that these wave forms represented cerebral tooth pulp-evoked potentials. Because tooth pulp-evoked potentials represent objective, quantifiable, nonverbal concomitants of central events associated with the perception of noxious stimuli, they may prove helpful in investigating acute experimental pain in man.

Transganglionic degeneration in the trigeminal main sensory nucleus (MSN) and pars interpolaris (PI) was studied in cats following dental lesions. At early survival times, three types of terminal alteration were seen in both MSN and PI: (1) flocculent degeneration, (2) neurofilamentous hyperplasia and, (3) glycogen accumulation. With longer survival times, the magnitude of these terminal alterations increases. Electron dense degeneration was only seen in the ventral half of PI. Phagocytosis of the altered terminals was also observed. The study suggests a plausible explanation for the variations observed in the CNS projection of primary afferents with degeneration and with HRP transport studies.

Cerebral-evoked potentials were used to study a 25-year-old man, the older of two siblings with congenital insensitivity to all noxious stimuli, gross impairment of temperature perception, and anhidrosis. Electrical stimulation of tooth pulp consistently eliciting pain and cerebral responses in normal subjects evoked neither cerebral potentials nor painful or other sensations in our patient. However, ordinarily painful electric shocks to the skin of his face evoked cerebral responses as well as sensations lacking disagreeable qualities. Those cerebral potentials elicited by electrical stimulation of the median nerve, clicks, and light flashes were within normal limits. These findings strongly suggest that a defect in transmission of noxious impulses presumably involving first order sensory neurons exists in our patient.

Following multiple tooth pulp extirpations, electron microscopic preparations show degenerating axons and synaptic terminals in the same region of the brain stem trigeminal nucleus previously demonstrating degeneration by light-optical methods. The observations confirm the phenomenon of transganglionic degeneration in this system and identify the class of central nervous system axons and synapses specifically related to innervation of the teeth.

The ultrastructure of degenerative changes within the ipsilateral trigeminal ganglion, and partes caudalis and interpolaris of the spinal trigeminal nucleus in the cat is described following the application of the potent toxin ricin to the tooth pulps of unilateral maxillary and mandibular posterior teeth, including the cuspids. Survival times ranged from 6 to 10 days. Typical changes identified within the ipsilateral trigeminal ganglion included myelin fragmentation and 'compartmentalization' of the axoplasm of medium-sized myelinated axons, while small myelinated and unmyelinated axons underwent a more variable response ranging from electron-lucent to electron-dense changes. The affected cell body was characterized by the presence of swollen, electron-lucent mitochondria, a reduction of cytoplasmic ribosomes and a filamentous hyperplasia. Other changes often included an eccentric nucleus and satellite cell proliferation. Degenerative changes often occurred in isolated elements surrounded by normal profiles, suggesting specificity of ricin within the trigeminal ganglion. Changes within brainstem axons showed both an electron-dense and a lucent, fragmenting type of axonal alteration. Terminal changes ranged from electron-dense to lucent and also included filamentous hyperplasia and 'hyperglycogenesis'. The altered axonal knobs contained round synaptic vesicles that were presynaptic to dendritic profiles and postsynaptic to terminals containing flattened synaptic vesicles. The above brainstem alterations were identified specifically in the following areas: ventrolateral, medial and dorsomedial pars interpolaris; the ventrolateral and mid-dorsal to dorsomedial areas of the marginalis and outer substantia gelatinosa layers of pars caudalis; and in ventral pockets corresponding to lamina V of the medullary dorsal horn. Dense alterations within terminals containing flattened synaptic vesicles that are typically presynaptic to primary afferents in these areas were rare findings, but along with vacuolization of dendritic profiles suggest a trans-synaptic effect possibly due to the exocytosis of ricin. The results are discussed in relation to different reports of dental projections and with regards to patterns of transganglionic degeneration.