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Tumor metastasis is the major cause of morbidity and mortality in patients with breast cancer. It is critical to identify metastasis enabling genes and understand how they are responsible for inducing specific aspects of the metastatic phenotype to allow for improved clinical detection and management. Protein kinase CE (PKCE), a member of a family of serine/threonine protein kinases, is a transforming oncogene that has been reported to be involved in cell invasion and motility. In this study, we investigated the role of PKCE in breast cancer development and progression. High-density tissue microarray analysis showed that PKCE protein was detected in 73.6% (106 of 144) of primary tumors from invasive ductal breast cancer patients. Increasing PKCE staining intensity was associated with high histologic grade (P = 0.0206), positive Her2/neu receptor status (P = 0.0419), and negative estrogen (P = 0.0026) and progesterone receptor status (P = 0.0008). Kaplan-Meier analyses showed that PKCE was significantly associated with poorer disease-free and overall survival (log-rank, P = 0.0478 and P = 0.0414, respectively). RNA interference of PKCE in MDA-MB231 cells, an aggressive breast cancer cell line with elevated PKCE levels, resulted in a cell phenotype that was significantly less proliferative, invasive, and motile than the parental or the control RNA interference transfectants. Moreover, in vivo tumor growth of small interfering RNA-PKCE MDA-MB231 clones was retarded by a striking 87% (P < 0.05) and incidence of lung metastases was inhibited by 83% (P < 0.02). PKCEdeficient clones were found to have lower RhoC GTPase protein levels and activation. Taken together, these results revealed that PKCE plays a critical and causative role in promoting an aggressive metastatic breast cancer phenotype and as a target for anticancer therapy. (Cancer Res 2005; 65(18): 8366-71)

BACKGROUNDThe survival of patients with head and neck squamous cell carcinoma (HNSCC) remains unaffected despite recent therapeutic advances. To reverse this trend, reliable and clinically applicable markers of tumor aggressiveness must be identified. One such marker may be the tumor‐associated macrophage content. The authors hypothesized that tumor‐associated macrophages contribute to HNSCC aggressiveness, and the objective of the current study was to prove this hypothesis using mRNA expression analysis and a large cohort of clinical specimens.METHODSOligonucleotide microarray analysis was performed on a prospective cohort of 20 patients with previously untreated oral cavity or oropharynx squamous cell carcinoma (OC/OP SCCA) and on normal oropharyngeal mucosa from 4 patients. After determining whether macrophage chemoattractants were produced by tumors, conditioned media from three HNSCC cell lines were used to quantify macrophage migration in an in vitro assay. A high‐density tissue microarray of 102 patients with previously untreated OC/OP SCCA was stained immunohistochemically for CD68 to identify tissue macrophages, and the results were correlated with clinicopathologic data and survival.RESULTSMonocyte chemoattractant protein 1 was up‐regulated significantly in tumors compared with normal mucosa (P = 0.0025; fold change = 1.89). All University of Michigan SCC tumor cell line conditioned media caused a significant increase in macrophage migration (P < 0.05). Tissue microarray data revealed that macrophage content of the primary tumor was associated strongly with lymph node metastasis (P < 0.0001), extracapsular lymph node spread (P = 0.0001), and advanced clinical disease stage (P = 0.0002). When it was evaluated along with other clinicopathologic data, the macrophage content was found to be an independent predictor of lymph node metastasis (P < 0.0001).CONCLUSIONSPrimary tumor macrophage content is a strong predictor of tumor aggressiveness in HNSCC. Cancer 2004. © 2004 American Cancer Society.

In¯ammatory breast cancer (IBC) is an aggressive form of breast cancer with a 5-year disease-free survival of less than 45%. Little is known about the genetic alterations that result in IBC. In our previous work, we found that WISP3 was speci®cally lost in human IBC tumors when compared to stage-matched, non-IBC tumors. We hypothesize that WISP3 has tumor suppressor function in the breast and that it may be a key genetic alteration that contributes to the unique IBC phenotype. The full-length WISP3 cDNA was sequenced and cloned into an expression vector. The resulting construct was introduced in to the SUM149 cell line that was derived from a patient with IBC and lacks WISP3 expression. In soft agar, stable WISP3 transfectants formed signi®cantly fewer colonies than the controls. Stable WISP3 transfectants lost their ability to invade and had reduced angiogenic potential. WISP3 transfection was eective in suppressing in vivo tumor growth in nude mice. Mice bearing WISP3 expressing tumors had a signi®cantly longer survival than those with vectorcontrol transfectant tumors. Our data demonstrate that WISP3 acts as a tumor suppressor gene in the breast. Loss of WISP3 expression contributes to the phenotype of IBC by regulating tumor cell growth, invasion and angiogenesis.

Members of the protein kinase C (PKC) family have long been studied for their contributions to oncogenesis. Among the ten different isoforms of this family of serine/threonine kinases, protein kinase Cε (PKCε) is one of the best understood for its role as a transforming oncogene. In vitro, overexpression of PKCε has been demonstrated to increase proliferation, motility, and invasion of fibroblasts or immortalized epithelial cells. In addition, xenograft and transgenic animal models have clearly shown that overexpression of PKCε is tumorigenic resulting in metastatic disease. Perhaps most important in implicating the epsilon isoform in oncogenesis, PKCε has been found to be overexpressed in tumor-derived cell lines and histopathological tumor specimens from various organ sites. Combined, this body of work provides substantial evidence implicating PKCε as a transforming oncogene that plays a crucial role in establishing an aggressive metastatic phenotype. Reviewed here is the literature that has led to the current understanding of PKCε as an oncogene. Moreover, this review focuses on the PKCε-mediated signaling network for cell motility and explores the interaction of PKCε with three major PKCε signaling nodes: RhoA/C, Stat3 and Akt. Lastly, the emerging role of PKCε as a tumor biomarker is discussed.

ObjectivesRecurrent respiratory papillomatosis (RRP) is a chronic disease of the respiratory tract that occurs in both children and adults. It is caused by the human papillomavirus (HPV), in particular low‐risk HPV6 and HPV11, and aggressiveness varies among patients. RRP remains a chronic disease that is difficult to manage. This review provides perspectives on current and future management of RRP.ResultsThe current standard of care is surgical excision, with adjuvant therapies as needed. Surgical management of RRP has evolved with the introduction of microdebriders and photoangiolytic lasers; the latter can now be used in the office setting. Numerous adjuvant pharmacologic therapies have been utilized with some success. Also, exciting preliminary data show that HPV vaccines may prolong the time to recurrence in the RRP population. There is also optimism that wide‐spread HPV vaccination could reduce RRP incidence indirectly by preventing vertical HPV transmission to newborns.ConclusionTo date, the biology of RRP is not well understood, although it has been noted to become more aggressive in the setting of immune suppression. Additional research is needed to better understand immune system dysfunction in RRP such that immunomodulatory approaches may be developed for RRP management.Level of Evidence4

The objective of the current study was to investigate the effects of Rap1GAP on invasion and progression of head and neck squamous cell carcinoma (SCC) and the role of matrix metalloproteinase (MMP) 9 and MMP2 in this process. Rap1GAP functions by switching off Rap1, the Ras-like protein that has been associated with carcinogenesis. Previous findings suggest that Rap1GAP acts as a tumor suppressor protein in SCC by delaying the G 1 -S transition of the cell cycle. However, cells transfected with Rap1GAP exhibit a more invasive phenotype than corresponding vector-transfected control cells. MMP2 and MMP9 are enzymes that mediate SCC invasion via degradation of the extracellular matrix. Using SCC cells transfected with empty vector or Rap1GAP, cell invasion and MMP secretion were determined by Matrigel assays and gelatin zymography, respectively. Rap1GAP upregulated transcription and secretion of MMP2 and MMP9, as assayed by quantitative reverse transcription-PCR and zymography. Furthermore, chemical and RNA interference blockade of MMP2/MMP9 inhibited invasion by Rap1GAP-transfected cells. Immunohistochemical staining of a human oropharyngeal SCC tissue microarray showed that Rap1GAP and MMP9 expression and staining intensity are correlated (P < 0.0001) and that, in early N-stage lesions of SCC, high MMP9 is prognostic of poor disease-specific survival (P < 0.05). Furthermore, Rap1GAP staining is correlated with MMP2 (P < 0.03). MMP2 in combination with N stage has a prognostic effect on time to indication of surgery at primary site. MMP2 intensity is also positively correlated with T stage (P < 0.015). In conclusion, Rap1GAP inhibits tumor growth but induces MMP2-and MMP9-mediated SCC invasion and tumor progression, suggesting a role for this protein as a biomarker for early N-stage, aggressive SCCs. [Cancer Res 2008;68(10):3959-69]

Nanog is a transcription factor that is well-established as a key regulator of embryonic stem cell (ESC) maintenance. Recent evidence demonstrates that Nanog is dysregulated and intimately involved in promoting tumorigenesis in part through regulation of the cancer stem cell (CSC) population. Elevated Nanog is associated with poorer outcome in numerous epithelial malignancies. Nanog is enriched in CSCs and ablation of Nanog is sufficient to reduce the CSC pool. Nanog has also been implicated to promote chemoresistance and epithelial-mesenchymal transition (EMT). Insight into the Nanog signaling cascade, upstream regulators and downstream effectors, is beginning to emerge but remains to be fully elucidated. This review highlights the current literature on the emerging role of Nanog in tumorigenesis and CSCs.