Electronic cigarettes are often touted as a safer alternative to tobacco smoke, but a new study suggests that this may not be the case, The Daily Mail reported.

Research recently presented at the American Association for Cancer Research annual meeting in San Diego, Calif., suggests that e-cigarettes can change gene expression in a similar way to tobacco.

"They may be safer [than tobacco], but our preliminary studies suggest that they may not be benign," study author Avrum Spira, a genomics and lung cancer researcher at Boston University, is quoted as saying by Digitaltrends.com.

For the study, researchers profiled the gene expressions of cells that were immortalized and grown in culture medium that had been exposed to e-cigarette vapor.

Spira and his colleagues found that bronchial cells grown in a medium exposed to e-cig vapor showed "strikingly similar" gene mutations to those grown in a medium exposed to tobacco smoke.

Spira emphasized that the changes are not identical.

Researchers said more research is needed to draw clear-cut conclusions, but the similarities may "be an indicators that e-cig vapor could potentially increase a user's risk of cancer, despite the fact that e-liquid is completely tobacco free and doesn't require combustion to be consumed," Digitaltrends.com reported.

The research is at a "very early stage" and therefore cannot establish that, like tobacco, e-cigarettes can cause cancer.

The next step for the team is to conduct further experiments on the genes altered by the e-cigarette vapor to determine their cancer-causing potential.

"These studies will determine the impact of e-cig exposure on lung carcinogenicity and provide needed scientific guidance to the FDA regarding the physiologic effects of e-cigs," Spira said.

E-cigarettes have been promoted as a safer alternative to conventional smoking because they vaporize liquid containing nicotine, rather than burning tobacco.

The findings were recently published in Nature.