In 1998, we reported that a significant proportion of breast and/or ovarian cancer families of French Canadian descent harbor specific germline mutations in BRCA1 or BRCA2 attributed to common founders. Here we report the frequency of previously described mutations (n ‫؍‬ 7) and 13 mutations identified in French Canadian families since 1998, in a new group of families (n ‫؍‬ 88). Four of the previously described mutations, 4446C>T, 2953delGTAinsC, 8765delAG and 6085C>T, account for 72% and 69% of mutation-positive families in previously (n ‫؍‬ 81) and recently ascertained groups, respectively. Only 2 of 13 recently identified mutations were found in more than 1 family: 3875delGTCT (n ‫؍‬ 2) and 3398delAAAAG (n ‫؍‬ 4). The 2 groups (ascertained pre-and post-gene discovery) did not differ significantly when distribution of mutations based on cancer syndrome phenotype and age of diagnosis or number of breast cancer cases were compared. Five common mutations accounted for a significant proportion (84%) of all mutationpositive families. The age of diagnosis of female breast cancer in mutation-negative families was significantly higher than that of the mutation-positive families (p<0.0001). The total number of cases of cancer per family was significantly lower in mutation-negative than mutation-positive families (p<0.001). Our results define a new mutation panel for screening BRCA1/2 mutations and the phenotype of mutation-positive families harboring the common mutations in the French Canadian population. © 2004 Wiley-Liss, Inc. Key words: BRCA1; BRCA2; French Canadian; founder mutationIn 1998, our group was the first to report that a significant proportion of breast and/or ovarian cancer families of French Canadian descent harbor specific mutations in BRCA1 and BRCA2 1 genes that confer a significantly increased lifetime risk of developing both breast cancer and ovarian cancer. [2][3][4][5] In the initial study that comprised 97 hereditary breast cancer (HBC) and hereditary breast and ovarian cancer (HBOC) families screened for only 4 specific variations in each gene, the BRCA1 4446CϾT and BRCA2 8765delAG mutations accounted for 68% (28 of 41) of mutation-positive families. 1 The BRCA1 2953delGTAinsC and 3768insA mutations, and BRCA2 2816insA and 6085GϾT mutations, were also identified more than once in independently ascertained families and were observed at similar frequencies, accounting for 4 to 10% of mutation-positive families. Although only specific mutations were screened in this analysis, the overall proportion of mutation-positive families was consistent with those observed in other reports in the general population where a comprehensive analysis of BRCA1 and/or BRCA2 was conducted. 6 -11

The results of this preliminary study suggest that weight control in adulthood through dietary energy intake restriction is an important factor for the prevention of BRCA-related BC risk.

Mammalian sulfotransferases (EC 2.8.2) are involved in many important facets of steroid hormone activity and metabolism. In this study, Arabidopsis AtST4a and AtST1 were identified and characterized as brassinosteroid sulfotransferases that appear to be involved in different aspects of hormone regulation. The two proteins share 44% identity in amino acid sequence, and belong to different plant sulfotransferase families. AtST4a was specific for biologically active end products of the brassinosteroid pathway. The enzyme sulfated brassinosteroids with diverse side-chain structures, including 24-epibrassinosteroids and the naturally occurring (22R, 23R)-28-homobrassinosteroids. AtST4a belongs to a small subfamily of sulfotransferases having two other members, AtST4b and -c. Among the three recombinant enzymes, only AtST4a was catalytically active with brassinosteroids. Transcript expression of AtST4 subfamily members was largely specific to the root. AtST4b- and -c transcript levels were induced by treatment with trans-zeatin, while AtST4a was repressed under the same conditions, supporting a divergent function of AtST4a. Co-regulation of AtST4b and -c correlated with their location in tandem on chromosome 1. AtST1 was stereospecific for 24-epibrassinosteroids, with a substrate preference for the metabolic precursor 24-epicathasterone, and exhibited catalytic activity with hydroxysteroids and estrogens. To gain more insight into this dual activity with plant and mammalian steroids, enzymatic activities of human steroid sulfotransferases toward brassinosteroids were characterized. The dehydroepiandrosterone sulfotransferase SULT2A1 displayed catalytic activity with a selected set of 24-epibrassinolide precursors, including 24-epicathasterone, with specific activities comparable to that measured for the endogenous substrate dehydroepiandrosterone. The comparable activity profiles of AtST1 and SULT2A1 suggest a similar architecture of the acceptor-binding site between the two enzymes, and may potentially reflect a common ability to conjugate certain xenobiotics.

Objective. To compare the effect of licofelone, NS-398 (an inhibitor of cyclooxygenase 2 [COX-2]), andBayX-1005 (an inhibitor of 5-lipoxygenase activating protein) on the production of leukotriene B 4 (LTB 4 ) and prostaglandin E 2 (PGE 2 ), and on cell biomarkers by human osteoarthritis (OA) subchondral osteoblasts.Methods. Primary in vitro osteoblasts were prepared from subchondral bone specimens obtained from OA patients and autopsy subjects. LTB 4 and PGE 2 levels were measured by enzyme-linked immunosorbent assay in conditioned media of osteoblasts incubated in the presence or absence of licofelone, NS-398, or BayX-1005. The effect of these drugs or of the addition of LTB 4 on alkaline phosphatase (AP) activity and osteocalcin release by OA and normal osteoblasts was determined. The presence of LTB 4 receptors in normal and OA osteoblasts was evaluated by Western blot analysis.Results. OA osteoblasts produced variable levels of PGE 2 and LTB 4 compared with normal osteoblasts. Licofelone, at the maximal dose used, inhibited production of PGE 2 and LTB 4 by OA osteoblasts by a mean ؎ SEM of 61.2 ؎ 6.4% and 67.0 ؎ 7.6%, respectively. NS-398 reduced PGE 2 production by 75.8 ؎ 5.3%. BayX-1005 inhibited LTB 4 production in OA osteoblasts by 38.7 ؎ 14.5% and marginally affected PGE 2 levels (reduction of 14.8 ؎ 5.3%). Licofelone dose-dependently stimulated 1,25-dihydroxyvitamin D-induced AP activity while inhibiting osteocalcin release. BayX-1005 partly reproduced these effects, but NS-398 failed to affect them. LTB 4 dose-dependently inhibited AP activity in OA osteoblasts, while its effect on osteocalcin depended on endogenous LTB 4 levels in these cells. In normal osteoblasts, LTB 4 dosedependently stimulated osteocalcin, whereas it failed to influence AP. LTB 4 receptors BLT1 and BLT2 were present in normal and OA osteoblasts.Conclusion.