Purpose: RhoB is a low molecular weight GTPase belonging to the Ras protein superfamily. Whereas most Rho proteins have been shown to have a positive role in proliferation and malignant transformation, the specific role of RhoB appears more divergent. We reported previously that RhoB inhibits cell proliferation in various human cancer cells. Here, we studied the specific role played by RhoB in human lung cancer.Experimental Design: We analyzed the expression of RhoB protein by immunostaining in human lung tissues ranging from normal to invasive carcinoma from different histological types in two large independent studies of, respectively, 94 and 45 samples. We then studied the cellular effect of RhoB overexpression in a model of lung cancer (A549, adenocarcinoma) and tumorigenicity in nude mice.Results: We showed in both studies that RhoB protein was expressed in normal lung and decreased dramatically through lung cancer progression (P < 0.01). Interestingly, RhoB expression was lost in 96% of invasive tumors and reduced by 86% in poorly differentiated tumors compared with the nonneoplastic epithelium. Moreover, the loss of expression of RhoB correlated significantly with tumor stage and proliferative index, whereas no correlation was found between RhoB and p53 or Bcl-2 expression. We then showed that ectopic expression of RhoB in lung cancer cell line A549 suppressed cell proliferation, anchorage-independent growth, and xenograft tumor growth in nude mice.Conclusions: RhoB loss of expression occurs very frequently in lung carcinogenesis, reinforcing its putative tumor suppressive activity, and raising the value of its potential use in cancer therapy.

Clinical trials hold great promise for cancer treatment; yet, Hispanic cancer patients have low rates of clinical trial participation. Lack of awareness and knowledge of clinical trials and language barriers may account for low participation rates. Patient education through audiovisual materials can improve knowledge of and attitudes toward clinical trials among Hispanic populations. In this study, 36 Hispanic cancer patients/survivors and caregivers in Florida and Puerto Rico participated in focus groups to aid in developing a Spanish-language DVD and booklet intervention designed to increase knowledge about clinical trials. Focus group results showed (a) low levels of knowledge about clinical trials, (b) uncertainty about why a physician would expect a patient to make a choice about treatment, and (c) desire for family participation in decision making. Respondents expressed various preferences for aspects of the DVD such as showing extended family in the DVD and physician explanations about key terms. On the basis of these preferences, the authors developed a creative brief for a DVD. The content of the DVD was reviewed by Hispanic community leaders and key stakeholders. A final DVD was created, in Spanish, using Hispanic patients and physicians, which contained the information deemed important from the focus groups and stakeholder interviews. The DVD is complete with companion booklet and currently undergoing a randomized control trial.