MySql, alternatives to repeating Select IN (Select()) when UNION

Question

I've been tackling this for a long time and I've decided I will ask to see if someone can suggest something before my head explodes.

Here is the query I'm running, it's just repeating the same sub-sub-query multiple times within the sub-queries. I wanted to see what ALTERNATIVE options I have to speed this up.

All I can think so far is running an initial query then inserting the results for a second query.

Thanks in advance for anyones time looking at this.

SELECT t2.* FROM TABLEA as t2 where
t2.link_id in 
(
    select t4.LinkA as link_list from TABLEB as t4
    where t4.LinkB in (
        select t1.id from TABLEC as t1 where t1.number in
        (
            (select t2.number from TABLEC as t2 where t2.id in 
                (
                select t3.link_id from TABLEA as t3 where t3.an like "%20278%"
                )
            )
        )
    )
    union

    select t4.LinkB as link_list from TABLEB as t4
    where t4.LinkB in (
        select t1.id from TABLEC as t1 where t1.part_number in
        (
            (select t2.number from TABLEC as t2 where t2.id in 
                (
                select t3.link_id from TABLEA as t3 where t3.an like "%20278%"
                )
            )
        )
    )
    union


    select t4.LinkA as link_list from TABLEB as t4
    where t4.LinkA in (
        select t1.id from TABLEC as t1 where t1.number in
        (
            (select t2.number from TABLEC as t2 where t2.id in 
                (
                select t3.link_id from TABLEA as t3 where t3.an like "%20278%"
                )
            )
        )
    )
    union

    select t4.LinkB as link_idlist from TABLEB as t4
    where t4.LinkA in (
        select t1.id from TABLEC as t1 where t1.number in
        (
            (select t2.number from TABLEC as t2 where t2.id in 
                (
                select t3.link_id from TABLEA as t3 where t3.an like "%20278%"
                )
            )
        )
    )
)