The diagnosis of certain melanocytic proliferations remains one of the most challenging areas in pathology. In recent times, fluorescence in situ hybridization (FISH) has emerged as a promising diagnostic aid to conventional microscopy. We previously showed that a 4-probe FISH assay targeting 6p25 (RREB1), 6q23 (MYB), Cep6 (centromere 6), and 11q13 (CCND1) could discriminate between histologically unequivocal melanomas and benign nevi with a sensitivity of 86.7% and specificity of 95.4%. However, the sensitivity of the assay is approximately 70% in melanomas with spitzoid morphology. Furthermore, differentiating true gains from tetraploidy may cause difficulties in interpretation by inexperienced examiners. Here we refine the current probe set to better target spitzoid melanomas and more easily distinguish cells with imbalanced copy number aberrations from tetraploid cells. Using FISH data from 3 training sets of 322 tumors, including 152 melanomas and 170 nevi, we identified 9p21, 6p25, 11q13, and 8q24 as a probe set with improved discriminatory power in differentiating melanomas from nevi. In a validation set of 51 melanomas and 51 nevi this probe set had a sensitivity of 94% and specificity of 98%, compared with the original probe set that had a sensitivity of 75% and specificity of 96% in the same validation cohort. We propose that by incorporating 9p21 into the 4-probe FISH assay, with a new diagnostic algorithm, this new probe set would have improved discriminatory power in melanocytic neoplasms and improved sensitivity for detecting spitzoid melanomas, as demonstrated by our previous studies.
The majority of new HIV infections occur in women as a result of heterosexual intercourse, overcoming multiple innate barriers to infection within the mucosa. However, the avenues through which infection is established, and the nature of bottlenecks to transmission, have been the source of considerable investigation and contention. Using a high dose of a single round non-replicating SIV-based vector containing a novel dual reporter system, we determined the sites of infection by the inoculum using the rhesus macaque vaginal transmission model. Here we show that the entire female reproductive tract (FRT), including the vagina, ecto- and endocervix, along with ovaries and local draining lymph nodes can contain transduced cells only 48 hours after inoculation. The distribution of infection shows that virions quickly disseminate after exposure and can access target cells throughout the FRT, with an apparent preference for infection in squamous vaginal and ectocervical mucosa. JRFL enveloped virions infect diverse CD4 expressing cell types, with T cells resident throughout the FRT representing the primary target. These findings establish a new perspective that the entire FRT is susceptible and virus can reach as far as the ovary and local draining lymph nodes. Based on these findings, it is essential that protective mechanisms for prevention of HIV acquisition must be present at protective levels throughout the entire FRT to provide complete protection.
The use of molecular diagnostic methods such as fluorescence in situ hybridization (FISH) for challenging melanocytic neoplasms is becoming more widespread. In light of the diagnostic difficulty they pose, spitzoid melanocytic neoplasms constitute an area of greatest potential utilization. In this study we wished to evaluate the sensitivity of the currently used melanoma FISH probe assay in a group of unambiguous spitzoid melanomas. On the basis of comparative genomic hybridization data, copy number losses at chromosome 9 have long been recognized as a frequent event in melanoma. In this study we wished to evaluate the efficacy of 9p21 as a potential FISH target and then evaluate the added benefit of reflexing the standard melanoma FISH assay, with FISH targeting 9p21 and the centromere of chromosome 9 (Cep9). Cep9 was included as a control to exclude inadequate hybridization or truncation as a source of homozygous deletions. We first studied a training set of 85 melanomas and 58 nevi with FISH targeting 9p21 and Cep9. As per previous methodology, 30 cells were enumerated. In the training set, the nevi had a mean number of cells with homozygous 9p21 loss of 0.97, with a standard deviation of 1.26. The melanomas had a mean of 7.1 and a standard deviation of 6.76. This difference was significant (P=2×10(-12)). On the basis of the training set, we identified a cutoff of 10 homozygous deletions to distinguish between melanoma and nevi. In a subsequent validation set consisting of 76 melanomas and 88 nevi, we found this cutoff to have a sensitivity of 33% and a specificity of 100%. Finally, in our group of 43 unequivocal spitzoid melanomas, standard FISH against chromosomes 6 and 11 was 70% sensitive. Homozygous 9p21 loss was present in 11 of 27 (41%) cases tested. By combining the standard melanoma FISH assay with the 9p21 FISH assay, a combined sensitivity of 85% was found. Among these 27 cases tested with 9p21, there were 7 cases that were negative by the standard melanoma FISH assay but that were positive by 9p21, suggesting that the 9p21 assay may be highly complementary to the standard melanoma FISH assay. Hence, in this study, we validated the efficacy of 9p21/Cep9 as a diagnostic FISH assay in melanoma, and demonstrated its complementary effect to the standard FISH assay. 9p21 may be particularly helpful in lesions with spitzoid morphology.
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