Is there any SOLID evidence supporting this claim?

The only possible carcinogenic electronic sources are high power (not medical) sources that emit x-rays or high power RF as a by product. These are few and far between and the likelyhood of them affecting the general public are as remote as Pluto. Workers in these environments have radiation badges which are checked regularly for exposure.

i have only seen one study that appeared to have some basis in fact and it was thoroughly discredited.

deaths of ham radio operators are regularly reported in the ARRL magazine, called "silent keys". researchers took those notices and concluded that the rate of cancer death was higher than the general population and they suggested a casual link.

the problem with the method was it did not correct for sex (ham radio is predominately a male sport), age (it is a hobby taken up by older people), or whether other factors (like smoking or hazardous employment) applied. When the ARRL re-examined the data, there were no apparent excess cancer deaths when controls were applied.

no absolutly not.