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  Newsletter December 2009

 

A short summary of the tests in run 27, run B8 and pilot run C2 is given below. Click on the epitope name to see the complete assessment for each marker.
The presentations now include tables with scoring details. The right column in the tables indicate the proportions of sufficient results obtained with optimal protocol settings: To calculate the latter we first identified protocol settings (range of primary Ab dilution, type of epitope retrieval etc.) that were needed to obtain an optimal result (if available), and hereafter found the proportion of sufficient results based on such protocols. The idea is better to illustrate the 'robustness' of primary Abs by adjusting for other protocol parameters.

Run 27 (General module) was accomplished September to December 2009. 142 laboratories participated and a total of 614 slides were assessed and the corresponding protocols analyzed. The overall distribution of marks were: optimal 37 %, good 31 %, insufficient 31 % (borderline or poor).

ASMA (alpha smooth muscle actin): 64 % sufficient results. The insufficient stains were mostly weak or false negative reactions due to incomplete heat induced epitope retrieval (HIER), too diluted antibody, and poor ready-to-use (RTU) systems. The mAb clone 1A4 in a RTU system calibrated by Dako (IS611/IR611) showed excellent performance. On the other hand, staining with the same clone 1A4 (both as a concentrate and a RTU format) on the BenchMark XT, Ventana, based on HIER in CC1 buffer caused a widespread nuclear cross reaction. It is highly recommended to use liver perisinusoidal cells for protocol calibration.

CD10: 74 % sufficient results. The insufficient stains were mainly charaterized by too weak or false negative reactions due to insufficient HIER or too a diluted primary antibody. It is highly recommended to use germinal centre B-cells for protocol calibration.

CDX2: Only 46 % sufficient results in this rather challenging test. The insufficient stains were mainly too weak or false negative reactions with the most used 'old' mAb clones CDX2-88 and AMT28. In contrast, the new mAb clone DAK-CDX2 showed superior performance, both as a concentrate and in an RTU system (IS080/IR080, DAKO). Also the rabbit mAb clone EPR2764Y seems promising.

CEA (Carcinoembryonic antigen): 75 % sufficient results. The insufficient stains were mostly due to the mAb clones PARLAM 4 and TF3H8-1 giving an unacceptable cross reaction with other CEA-like proteins. In contrast the mAb clones COL-1 and II-7 performed well both as concentrates and in RTU systems.

Prostein (P501S): 11 labs took the opportunity to use this alternative to PSA.
73 % sufficient result. The insufficient stains were due to inappropriate calibration of the Ab concentration.

PSA (prostate specific antigen): 76 % sufficient results. The insufficient stains were mostly due to inapopropriate calibration of the Ab concentration.

The General module assessor group, from left: Elin Borgen, Heikki Helin, Mogens Vyberg, Jan Klos and Søren Nielsen.


Run B8 (Breast cancer module)
was accomplished in parallel with run 27 (see above). 157 laboratories participated and a total of 443 slides were assessed.

ER (Estrogen receptor alpha): In this 8th test, 74 % of the 144 stains were sufficient (marked optimal or good). The insufficient stains were mostly too weak reactions due to too diluted antibody or insufficient HIER. However, impaired morphology due to excessive HIER was also seen. Taken into consideration the therapeutic consequences of ER testing, it is not satisfying that about 1 out of 4 labs still produce borderline or poor results.

HER-2: In this 9th test 72% of the 136 stains were marked optimal or good. PATHWAY® (rabbit mAb clone 4B5, Ventana) continuously give a very high rate of sufficient results: 95 % optimal and 5 % good in this test. HercepTest (Dako) gave 81 % sufficient results when adjusted for labs not following the company's protocol guidelines. As for the poor results, Dako will offer detailed analysis of staining procedures in each lab, on site where feasible. Once again NordiQC must warn against using in house systems, which have unacceptable low pass rates.

p63: 95 % sufficient results, which is one of the most successful tests. Still many protocols could be optimized, particularly by increasing the Ab concentration.

SMH (smooth muscle heavy chain myosin): In this first test, 79 % of 19 stains were sufficient. Efficient HIER is mandatory: an alkaline buffer is recommended. Follicular dendritic cells are low expressing cells and should be used as the critical indicator in tonsils/lymph nodes used for control.

Run C2 (CISH/SISH HER-2 pilot module) was accomplished in parallel with run B8. 34 laboratories participated in this second pilot run.

CISH/SISH HER-2: 68 % of the stains were sufficient. Both dual and single colour systems could be used to obtain an optimal staining. NordiQC is grateful to Dako, Ventana/Roche and Zymed/Invitrogen for sponsoring this testmodule (runs C1 and C2).
CISH/SISH tests will in 2010 be offered as a part of the Breast cancer module.

7th December 2007
Mogens Vyberg
Scheme director

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Last update 11-12-2009