left-handedness seems to be associated with the risk of breast cancer
 

and an hypothesis of why that may be:

Br J Cancer. 2007 Aug 7; [Epub ahead of print]
Left-handedness and risk of breast cancer.

Fritschi L, Divitini M, Talbot-Smith A, Knuiman M.
1Western Australian Institute for Medical Research, Nedlands, Perth, Western Australia 6009, Australia.
Left-handedness may be an indicator of intrauterine exposure to oestrogens, which may increase the risk of breast cancer. Women (n=1786) from a 1981 health survey in Busselton were followed up using death and cancer registries. Left-handers had higher risk of breast cancer than right-handers and the effect was greater for post-menopausal breast cancer (hazard ratio=2.59, 95% confidence interval 1.11-6.03).British Journal of Cancer advance online publication, 7 August 2007; doi:10.1038/sj.bjc.6603920 www.bjcancer.com.
PMID: 17687338 [PubMed - as supplied by publisher]

At least I know why....OK, so Left handed does not just mean we are in our right mind
For the record, Left Handed ER - PR -

Right handed here, and my BC was ER- PR-

Same as Brenda. Right handed - er/pr neg.

Mary Jo

I remember my surgeon asking me this on the initial questionnaire - left handed and ER/PR- and her/2neu+++

Regards,

I'm right handed, er/pr-.

Linda
S. Mississippi

Left handed. ER+, PR-, HER2+++

also right handed and er/pr-, her2+

Left-handed, ER-/PR+, Her2+.....go figure...
Susan C

I'm a lefty and ER/PR- and Her2Neu+. Also clumsy as Hell so I'll never live to be 100, but I'm damn well trying. :-)

Left handed, Er & Pr weakly positive. Her2/neu 3+++.

Chelee

Me Too,
Left Handed, daughter and grand daughter left handed. However on a more positive note, my aunt was also left handed and no br. ca.

Left handed
ER/PR+
Her2+++

Left handed, er/pr-. I have a daughter who is left handed.

Mostly right handed, but definitely right brained. ER+, PR+, Her2 +++. Somewhat ambidextrous, which has really come in handy this past two weeks since my surgery.

Leslie

lefty here
 

Left handed
ER/PR+
Her2+++

right handed, ER-/PR- HER2+++

Left handed, ER/PR-, Her2 +++

Looks like quite a few lefties here!

Lefty here! ER/PR-, Her2 +++

Love, Kelly

Very right handed. Triple pos. Just don't know. BB