Apolipoprotein E polymorphism and age at onset of Alzheimer's disease in a quadriethnic sample.

BACKGROUND: The relationship between the apolipoprotein E (ApoE) genotype and the risk for developing Alzheimer's disease (AD) or age at onset of AD is relatively well established in Caucasians, but less established in other ethnicities. We examined the association between the ApoE genotype and age at onset of AD in a quadriethnic group of community-dwelling AD patients. METHODS: AD patients were evaluated at 2 university-based outpatient memory disorder clinics. The ethnic distribution was as follows: Caucasians (n = 1,083), Hispanics (n = 55), African Americans (n = 84) and Koreans (n = 87). All were diagnosed with probable AD according to NINCDS-ADRDA diagnostic criteria. RESULTS: After adjusting for ethnicity, the ε4 allele was significantly associated with earlier age at onset (p < 0.0001) for the combined group. Within ethnic groups, the effect of Apo ε4 on age at onset was significant in Caucasians (p < 0.0001) and African Americans (p < 0.05), but nonsignificant in Koreans (p = 0.43) and in the smaller Hispanic (p = 0.07) group. CONCLUSIONS: The association between Apo ε4 and younger age at onset was significant in Caucasians and African Americans, where the ε4 allele was also most frequent. This study suggests that the impact of ApoE polymorphism on age at onset of AD may be different among distinct ethnic groups.

Sentinel lymph node biopsy for sebaceous cell carcinoma and melanoma of the ocular adnexa.

OBJECTIVE: To provide clinical details and long-term outcome data for a series of patients with eyelid or conjunctival melanoma or eyelid sebaceous cell carcinoma who underwent sentinel lymph node (SLN) biopsy. DESIGN: Retrospective interventional case series with review of clinical records and pathologic specimens. SETTING: Tertiary comprehensive cancer center. PATIENTS: Twenty-five consecutive patients treated at 1 institution for eyelid or conjunctival melanoma or eyelid sebaceous cell carcinoma from December 2000 to October 2004. INTERVENTIONS: Surgical removal of the eyelid or conjunctival tumor and SLN biopsy. MAIN OUTCOME MEASURES: Local treatment modalities; lymphatic basins in which SLNs were identified; status of SLNs; false-negative rate; and long-term patterns of local recurrence, regional and distant metastasis, and survival. RESULTS: Seven patients had conjunctival melanoma, 8 had eyelid-margin melanoma with a considerable palpebral conjunctival component, and 10 had eyelid sebaceous cell carcinoma. The SLNs were identified in all but 1 patient by using technetium Tc 99m sulfur colloid as a tracer. Intraoperatively, in 16 patients in whom blue dye was used in addition to technetium Tc 99m sulfur colloid during mapping, no SLN was blue. One patient with conjunctival melanoma and 1 patient with eyelid melanoma had a histologically positive SLN. Two patients with eyelid melanoma and 2 patients with eyelid sebaceous cell carcinoma had negative findings from SLN biopsy but developed recurrence in their regional lymph nodes during the follow-up period. Overall, during follow-up, 2 of 10 patients with sebaceous cell carcinoma (20%) and 5 of 15 patients with eyelid or conjunctival melanoma (33%) had regional lymph node metastasis. Four patients with melanoma who had regional metastasis also developed distant organ metastasis. Two patients with sebaceous cell carcinoma--1 with regional metastasis and 1 without--developed distant organ metastasis. CONCLUSIONS: The detection of histologically positive SLNs in this series of patients may justify further study of SLN biopsy for high-risk patients with ocular adnexal melanoma or eyelid sebaceous cell carcinoma. The false-negative rate is higher than that reported for SLN biopsy at most other anatomic sites. Patients with negative findings from SLN biopsy still require careful long-term follow-up because they may develop regional or distant metastasis.