"regarding" "concerning" etc. at the beginning of a sentence

[herbivorie]

Can "regarding" "concerning" etc. be used at the beginning of a sentence, like "with regard to"?
For example,

1.Regarding the item you sent, there are some points I'd like to discuss with you.
2. Concerning the item you sent, there are some points I'd like to discuss with you.
3. In relation to the item you sent, there are some points I'd like to discuss with you.
4. As to the item you sent, there are some points I'd like to discuss with you.

Also, please tell me if there are other options I can use at the beginning of a sentence. (I know it's incorrect to use "about" at the beginning of a sentence like this.)

Thank you.

 

[probus]

I have heard all of them, and also "as regards." So my answer is yes, they can be so used.