Duration of the Presence of Infectious Zika Virus in Semen and Serum.

Zika virus (ZIKV) has recently caused a large epidemic in the Americas that is associated with birth defects. Although ZIKV is primarily transmitted by Aedes mosquitoes, ZIKV RNA is detectable in blood and semen of infected individuals for weeks or months, during which sexual and other modes of transmission are possible. However, viral RNA is usually detectable longer than infectious virus is present. We determined the frequency of isolation of infectious virus from semen and serum samples prospectively obtained from a cohort of patients in Puerto Rico. We confirmed isolation of infectious virus on the basis of a tissue culture cytopathic effect, an increase in virus genome copy equivalents (GCE), and positive results of immunofluorescence analysis; virus in infected cells was quantitated by flow cytometry. These criteria confirmed the presence of infectious virus in semen specimens from 8 of 97 patients for up to 38 days after initial detection when virus loads are >1.4 × 106 genome copy equivalents/mL. Two serum isolates were obtained from 296 patients. These findings can help guide important prevention guidelines for persons that may potentially be infectious and transmit ZIKV sexually.

Differences in Smad4 expression in human papillomavirus type 16-positive and human papillomavirus type 16-negative head and neck squamous cell carcinoma.

The SMADs are a group of interrelated proteins that mediate transforming growth factor beta (TGF-beta) signaling. Upon TGF-beta binding the TGF-beta type I receptor phosphorylates Smad2 and Smad3, which then complex with Smad4 and translocate to the nucleus, with subsequent activation of target genes. Disruption of TGF-beta signaling is thought to contribute to the development of head and neck squamous cell carcinomas (HNSCC). Alterations in the function of the DPC4/Smad4 tumor suppressor gene have been found to inactivate TGF-beta signaling in several tumor types. For example, DPC4/Smad4 is lost or mutated in colorectal, pancreatic, and esophageal cancers. In addition, DPC4/Smad4 transcriptional activity and TGF-beta ability to inhibit DNA synthesis is blocked by the E7 protein of the human papillomavirus type 16 (HPV16) in cervical carcinoma cell lines. HPV16 infection is a risk factor for the development of a subset of HNSCC. This study was undertaken to investigate a potential correlation between expression of components of the TGF-beta signaling pathway and HPV16 status in HNSCC tumors. We examined the expression of TGF-beta signaling proteins Smad2, Smad2-P, and Smad4 by immunohistochemistry in 27 HPV16-negative and 16 HPV16-positive HNSCCs. We compared the expression patterns and assessed their relationship to HPV16 status. No significant differences were detected between HPV16-positive and HPV16-negative tumors in the expression of Smad2 and Smad2-P. Smad4 expression, however, was decreased in 56% of the HPV16-positive tumors and in 39% of HPV16-negative tumors. This difference was statistically significant (P = 0.01) suggesting that loss of Smad4 expression may be involved in HPV16-induced carcinogenesis of HNSCC.

High frequency of HPV16-associated head and neck squamous cell carcinoma in the Puerto Rican population.

BACKGROUND: Recent evidence has accumulated suggesting that human papillomavirus (HPV) plays a role in the development of head and neck squamous cell carcinoma (HNSCC). HPV16 is the most common of the HPV subtypes associated with oral and laryngeal malignancies. This study estimated the prevalence of HPV16 DNA in Puerto Rican patients with HNSCC. METHODS: DNA was extracted from frozen tissue of 118 HNSCCs. Genomic DNA was screened for the presence of HPV16 DNA with E6-specific and E7-specific primers. RESULTS: HPV16 was detected in tumor tissue of 52 patients (44%) with HNSCC. The oropharynx had a slightly higher incidence of HPV16 DNA. Fifteen of 66 patients with HPV16-negative HNSCC later had recurrences. Positivity for HPV16 was independent of the tumor grade, tumor stage, nodal status, and tobacco or alcohol use. The 3-year survival rate was higher in HPV16-positive patients than in HPV16-negative patients (36% vs 21%). CONCLUSIONS: Our findings suggest that HPV16 may play a role in the etiology of a subgroup of HNSCC in Puerto Ricans. Overall survival times of the HPV16-positive patients were not significantly different from those of HPV16-negative patients. Increasing our understanding of the role of HPV16 in the etiology of HNSCC might facilitate the development of new treatment modalities for this subgroup of HNSCC.