Context Most hereditary ovarian cancers are associated with germline mutations in BRCA1 or BRCA2. Attempts to define the clinical significance of BRCA mutation status in ovarian cancer have produced conflicting results, especially regarding survival.Objective To determine whether hereditary ovarian cancers have distinct clinical and pathological features compared with sporadic (nonhereditary) ovarian cancers. Design and SettingRetrospective cohort study of a consecutive series of 933 ovarian cancers diagnosed and treated at our institution, which is a comprehensive cancer center as designated by the National Cancer Institute, over a 12-year period (December 1986 to August 1998). PatientsThe study was restricted to patients of Jewish origin because of the ease of BRCA1 and BRCA2 genotyping in this ethnic group. From the 189 patients who identified themselves as Jewish, 88 hereditary cases were identified with the presence of a germline founder mutation in BRCA1 or BRCA2. The remaining 101 cases from the same series not associated with a BRCA mutation and 2 additional groups (Gynecologic Oncology Group protocols 52 and 111) with ovarian cancer from clinical trials (for the survival analysis) were included for comparison.Main Outcome Measures Age at diagnosis, surgical stage, histologic cell type and grade, and surgical outcome; and response to chemotherapy and survival for advancedstage (III and IV) cases. ResultsHereditary cancers were rarely diagnosed before age 40 years and were common after age 60 years, with mean age at diagnosis being significantly younger for BRCA1-vs BRCA2-linked patients (54 vs 62 years; P= .04). Histology, grade, stage, and success of cytoreductive surgery were similar for hereditary and sporadic cases. The hereditary group had a longer disease-free interval following primary chemotherapy in comparison with the nonhereditary group, with a median time to recurrence of 14 months and 7 months, respectively (PϽ.001). Those with hereditary cancers had improved survival compared with the nonhereditary group (P=.004). For stage III cancers, BRCA mutation status was an independent prognostic variable (P = .03). ConclusionsAlthough BRCA-associated hereditary ovarian cancers in this population have surgical and pathological characteristics similar to those of sporadic cancers, advancedstage hereditary cancer patients survive longer than nonhereditary cancer patients. Age penetrance is greater for BRCA1-linked than for BRCA2-linked cancers in this population.
Mutation in leucine-rich-repeat kinase 2 (LRRK2) is a common cause of Parkinson disease (PD). A disease-causing point mutation R1441H/G/C in the GTPase domain of LRRK2 leads to overactivation of its kinase domain. However, the mechanism by which this mutation alters the normal function of its GTPase domain [Ras of complex proteins (Roc)] remains unclear. Here, we report the effects of R1441H mutation (Roc R1441H ) on the structure and activity of Roc. We show that Roc forms a stable monomeric conformation in solution that is catalytically active, thus demonstrating that LRRK2 is a bona fide self-contained GTPase. We further show that the R1441H mutation causes a twofold reduction in GTPase activity without affecting the structure, thermal stability, and GDP-binding affinity of Roc. However, the mutation causes a twofold increase in GTP-binding affinity of Roc, thus suggesting that the PD-causing mutation R1441H traps Roc in a more persistently activated state by increasing its affinity for GTP and, at the same time, compromising its GTP hydrolysis.M utation in leucine-rich-repeat kinase 2 (LRRK2) is a common cause of Parkinson disease (PD) (1-5). LRRK2 is a large (2,527-aa) multidomain protein consisting of seven putative domains (2), including a Ras-like GTPase domain called Ras of complex proteins (Roc), followed by a domain called C-terminal of Roc (COR), which is then followed by a kinase domain (Kin). It remains unclear how perturbations of these activities result in disease; however, the most common mutation in LRRK2-associated PD, G2019S in the kinase domain, shows higher kinase activity than wild type; therefore, its overactivation might be associated with disease pathogenesis (6).The tandem Roc-COR-Kin arrangement suggests that their activities might be coupled such that the GTPase activity of Roc might modulate the kinase activity. Indeed, several studies have shown that GTP binding to the Roc domain regulates the activity of the Kin domain (7,8). Moreover, a PD-associated mutation in the Roc domain (R1441C) has been shown to have higher kinase activity (9), thus suggesting that mutations in the Roc domain, also up-regulate kinase activity.Understanding the function of Roc and its mechanism of action is important for understanding the mechanism of PD pathogenesis and therapeutic development. However, because of the lack sufficient quantity of protein samples amendable for detailed investigations, the biochemical properties and enzymatic activities of the Roc domain of LRRK2 are poorly understood.Here, we describe a stably folded construct of human Roc domain that enabled us to investigate quantitatively its biochemical and enzymatic properties. The results revealed that a PD-causing mutation R1441H in the Roc domain renders it less active at hydrolyzing GTP, as well as having higher affinity for GTP, than its wild-type counterpart, thereby increasing the residence time of its GTP-bound "active state," which is associated with PD pathogenesis (8). Results and DiscussionConstruction of a Stable Human LRR...
Women with BRCA founder mutations are at increased risk for breast cancer-related events after breast conservation. However, mutation status is not an independent predictor of survival and should not influence decisions regarding adjuvant therapy. The increased contralateral breast cancer risk in women heterozygous for BRCA mutations mandates careful surveillance.
BACKGROUND The high mortality associated with ovarian carcinoma is largely a reflection of the inability to diagnose the disease at an early stage; the identification of a histologic lesion or molecular marker associated early stages of transformation would represent an important advance in understanding the natural history of this cancer. The existence of individuals with germline mutations in the ovarian and breast carcinoma susceptibility gene BRCA1 represents a unique opportunity to search for such premalignant alterations in ovarian tissues that are at unusually high risk for tumorigenesis. In this study, the authors addressed the hypothesis that pathologically normal ovaries removed from BRCA1 heterozygotes are likely to display premalignant histologic, molecular, and/or cell biologic alterations that may provide insight into early stages of ovarian tumorigenesis. METHODS Ovarian tissues from 18 BRCA1 heterozygotes and from 20 age‐matched controls were examined in a blinded fashion for histologic evidence of surface epithelial pseudostratification, epithelial inclusion cysts, deep cortical invaginations of surface epithelium, increased stromal cell activity, and surface papillomatosis. Immunohistochemical analyses for expression of BRCA1, p53, and ERBB‐2 and quantitation of cell proliferation (Ki‐67 expression) and apoptosis (TUNEL assay), were also performed on all specimens. RESULTS Although histologic alterations were observed, there was no difference in frequency between cases and controls. Analysis of BRCA1 expression revealed ubiquitous nuclear immunoreactivity in the surface epithelial cells of all ovaries. Similarly, no evidence was found of p53 overexpression in any ovarian tissue or of a difference in ERBB‐2 expression between cases and controls. Finally, no differences were observed in epithelial cell proliferation or apoptosis. CONCLUSIONS Clinically, normal ovaries from BRCA1 heterozygotes do not show evidence of premalignant alterations in histology, molecular markers, cell proliferation, or apoptosis, indicating that such changes are likely rare. Cancer 2000;89:383–90. © 2000 American Cancer Society.
A male member of a large HNPCC kindred, affected by primary malignancies of the breast and colon, was identified. This individual was found to harbor a germline mutation of the MLH1 mismatch repair gene previously shown to segregate with disease in this kindred. The breast tumor exhibited somatic reduction to homozygosity for the MLH1 mutation, and microsatellite instability was evident in the breast tumor. We conclude that hereditary male breast cancer can occur as an integral tumor in the HNPCC syndrome.
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