Genomics and premalignant breast lesions: clues to the development and progression of lobular breast cancer

Advances in genomic technology have improved our understanding of the genetic events that parallel breast cancer development. Because almost all mammary carcinomas develop in the terminal duct lobular units of the breast, understanding the events involved in mammary gland development make it possible to recognize those events that, when altered, contribute to breast neoplasia. In this review we focus on lobular carcinomas, discussing the pathology, development, and progression of premalignant lobular lesions from a genomic point of view. We highlight studies utilizing genomic approaches and describe how these investigations have furthered our understanding of the complexity of premalignant breast lesions

The Nature and frequency of cognitive deficits in children with neurofibromatosis type 1

Objective: To assess the frequency and severity of specific cognitive deficits in children with neurofibromatosis type 1 (NF1) in a large unbiased cohort. Methods: Extensive cognitive assessments were performed in 81 children with NF1 ages 8 to 16 years and their performance was compared with that of 49 unaffected sibling controls. Results: Eighty-one percent of the children with NF1 had moderate to severe impairment in one or more areas of cognitive functioning. Although 51% of children with NF1 performed poorly on tasks of reading, spelling, and mathematics, specific learning disabilities (as defined by IQ-achievement discrepancies) were present in only 20% of the children. Sustained attention difficulties were present in 63% of children with NF1, with 38% of children with NF1 fulfilling the diagnostic criteria for attention deficit-hyperactivity disorder. The NF1 neuropsychological profile is characterized by deficits in perceptual skills (visuospatial and visuoperceptual), executive functioning (planning and abstract concept formation), and attention (sustained and switching). Interestingly, both verbal and visual memory was unaffected in NF1 children, and their memory skills were in general stronger than their level of general intellectual function. Although both expressive and receptive language skills were significantly impaired in NF1 children, they appeared to be relatively better preserved than visuospatial abilities once IQ is taken into account. Conclusion: There is an extremely high frequency of cognitive problems in children with neurofibromatosis type 1, making cognitive dysfunction the most common complication to affect quality of life in these children.8 page(s

Learning disabilities in children with neurofibromatosis type 1 : subtypes, cognitive profile, and attention-deficit-hyperactivity disorder

Cognitive deficits are the most common complication in children with neurofibromatosis type 1 (NF1), and academic achievement is broadly affected. There is a lack of consensus in the literature regarding the frequency of general and specific learning disabilities, which seems to be related to the lack of a consensus on diagnostic criteria. The present study examined the frequency of specific learning disabilities (SLDs) in NF1, using an intellect-achievement discrepancy for diagnosis, as well as general learning difficulty associated with a lowering of general intellectual ability. The cohort consisted of 81 children with NF1 (43 males, 38 females; mean age 11y 6mo [SD 2y 4mo]; range 8y–16y 9mo) and 49 comparison children (20 males, 29 females; mean age 12y [SD 2y 6mo]; range 8y 2mo–16y 8mo). Problems with academic achievement were present in 52% of children with NF1; however, only 20% of the children with NF1 were diagnosed with an SLD (32% had more general learning problems). Only males with NF1 were at significant risk for SLD, and Verbal IQ<Performance IQ discrepancies were predictive of the presence of an SLD. There was a significant comorbidity of literacy-based learning disabilities and attention-deficit-hyperactivity disorder. We were able to define three subtypes of children with NF1 having distinct cognitive profiles, each with important implications for assessment and remediation.5 page(s

Assessment of executive function and attention in children with neurofibromatosis type 1 : relationships between cognitive measures and real-world behavior

The aim of this study was to examine functional attention and executive deficits present in everyday living in a large sample of children with neurofibromatosis type 1 (NF1). Data are presented from 199 children with NF1 and 55 unaffected sibling controls who were administered the Behavior Rating Inventory of Executive Function (BRIEF) and Conners' ADHD DSM-IV Scales (CADS). Convergent validity was examined by correlating scale scores from these functional measures with scores from traditional cognitive measures of attention and executive function. Results indicated global functional attention and executive deficits in children with NF1. Relationships between functional impairments and scores on cognitive measures were inconsistent; at best, the magnitude of these relationships was in the moderate range, yet there was also a lack of association between many cognitive tasks and the functional skills they purport to assess. Findings suggest that cognitive and functional measures may tap different constructs and that neuropsychological evaluations should be supplemented with functional assessment tools to provide a more ac curate and sensitive encapsulation of a child's strengths and weaknesses to guide remediation programs.17 page(s

T2 hyperintensities in children with neurofibromatosis type 1 and their relationship to cognitive functioning

Background: Neurofibromatosis type 1 (NF1) is a single gene disorder associated with a high frequency of cognitive deficits and a complex cognitive phenotype. These cognitive deficits have been associated with focal areas of high signal intensity on T2 weighted MRI images but the relationship remains controversial. Method: A cohort of 76 children with NF1 and 45 unaffected sibling controls (aged 8–16 years) underwent extensive neuropsychological assessment, with the NF1 children having MRI examinations. Results: The presence or number of T2 hyperintensities (T2H) was not associated with cognitive dysfunction. However, the location of discrete (well circumscribed) T2H in the thalamus was associated with severe and generalised cognitive impairment. More diffuse lesions in the thalamus were also associated with reductions in IQ but the effects were less marked compared with the discrete lesions. Comparing children with NF1 to their unaffected siblings revealed more subtle effects of the lesions on cognitive ability. Conclusions: T2H cannot be used in general as a radiological marker for cognitive deficits in children with NF1; however, lesions in the thalamus are strongly associated with cognitive impairment. It is possible that lesions in the thalamus in conjunction with more general thalamic hypometabolism may compound the level of thalamic dysfunction, resulting in cognitive deficits well beyond those produced by T2H in other regions.4 page(s