results of ER, PR, her2 testing depend on whether specimen formalin-fixed promptly!!!

Lani · 09-09-2009, 03:20 AM

recommendation of this paper--Should be fixed within one hour, should not be stored overnight!!! Wonder how many statistics, results of treatment have been modified by this variable!! Take nothing for granted, it seems.

1: Mod Pathol. 2009 Sep 4. [Epub ahead of print]

Delay to formalin fixation effect on breast biomarkers.

Khoury T, Sait S, Hwang H, Chandrasekhar R, Wilding G, Tan D, Kulkarni S.
Department of Pathology, Roswell Park Cancer Institute, Buffalo, NY, USA.
Delay to formalin fixation may invalidate hormone receptors and HER2 analyses. Invalid results of tumor markers could significantly alter the type of adjuvant therapy a patient receives and potentially impact outcome. The purpose of this study was to determine the effects of progressive delay to formalin fixation on breast cancer biomarkers. Ten palpable invasive breast cancers were resected and underwent immediate gross evaluation. For each case, the procured tumor was divided into eight parts and consecutively fixed after 0, 10, 30 min, 1, 2, 4, and 8 h; one section was kept in saline and stored overnight at 4 degrees C. Two tissue microarray blocks were constructed. Estrogen and progesterone receptors and HER2 immunohistochemistry and fluorescence in situ hybridization were carried out. Statistical analyses including non-parametric sign test, exact McNemar's test and Page's L test were used. All 10 cases were invasive ductal carcinomas. Q score >/=6 was identified in five cases for estrogen receptor and four for progesterone receptor. Mean Q score started to decline at the 2 h mark for estrogen receptor and 1 h mark for progesterone receptor. Lowest score was at 8 h mark for estrogen receptor and overnight for progesterone receptor. HER2 fluorescence in situ hybridization started to be compromised for interpretation at the 1 h mark and became statistically significant at the 2 h mark (P<0.03). To avoid delay to formalin fixation as a factor negatively affecting on breast biomarkers, we recommend not to delay formalin fixation for more than 1 h and not to store specimens overnight.Modern Pathology advance online publication, 4 September 2009; doi:10.1038/modpathol.2009.117.
PMID: 19734848

Hopeful · 09-09-2009, 06:59 AM

Lani, this abstract refers to IHC and FISH testing, correct? Since the Oncotype test is also performed on formalin fixed tissue, I am guessing this could also affect those scores?

This study speaks to one of the "elephants in the room" in bc - the inconsistency in reproducing biomarker results among labs. Imagine how this can skew clinical trial results. We may have a better idea of which drugs work best in which patients if we can get the biomarker testing up to snuff.

Thanks for posting.

Hopeful

Lani · 09-09-2009, 07:47 AM

the oncotype dx relies on RNA for its results. This study should be repeated specifically looking for RNA degradation if formalin fixation is not performed promptly. Mammaprint and other microgene arrays are usually performed on fresh frozen samples. I wonder how:"fresh frozen" is defined? Within one minute of removal? Five minutes? one hour???

Lots of elephants in the room here!

Rich66 · 09-12-2009, 11:50 AM

Yeah...anyone have any idea how many samples are fixed before the 1 hour mark? This combined with heterogeneity of the (partially sampled) tumor(s) itself really begs for a more comprehensive approach. Serum tests seem like a good first step. Now..do serum tests have similar time sensitive issues? Hmmm. How about temperature? Elephants form a line outside the room.

sarah · 09-12-2009, 12:03 PM

wow! very interesting!

Hopeful · 09-14-2009, 02:37 PM

Here is a link to a discussion Neal Love had with Dr. Julie Gralow on this topic earlier this year: http://www.researchtopractice.com/br...her2-testing-0

Of interest:

"From a surgical perspective, we have to be cognizant of the fact that tissue fixation is critical and if a sample is not put in fixative in an appropriate amount of time, all bets are off in terms of the results. It can entirely alter the ER and HER2 staining. When this occurs, we don’t necessarily know how to treat the patient."

Hopeful