Microsatellite instability analysis of bilateral breast tumors suggests treatment-related origin of some contralateral malignancies.

Purpose: High-frequency microsatellite instability (MSI-H) occurs frequently in colorectal cancers and some other tumor types, but is very uncommon in breast cancer. In the earlier study devoted to microsatellite analysis of allelic imbalances, the authors accidentally detected several MSI-H tumors in patients with the bilateral form of breast cancer (biBC). The present study was designed to examine this unexpected phenomenon in more detail.

Expression of inhibitor of apoptosis proteins in small- and non-small-cell lung carcinoma cells.

Small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) cells both initiate apoptotic signaling, resulting in caspase activation, after treatment with anti-cancer agents. However, in contrast to SCLC cells, NSCLC cells do not fully execute apoptosis. The apoptotic process in NSCLC cells seems to be blocked downstream of caspase activation, thus the failure of NSCLC cells to execute apoptosis could result from inhibition of active caspases by inhibitor of apoptosis proteins (IAPs).

Concordance of allelic imbalance profiles in synchronous and metachronous bilateral breast carcinomas.

Bilateral breast cancer (biBC) is a common form of breast cancer; however, it has not been subjected to systematic comparative genetic studies. We allelotyped 28 biBCs on 14 chromosomal arms, addressing 2 lines of questions: (i) does comparison of genetic profiles disclose contralateral metastases misdiagnosed as second primaries? and (ii) do shared environmental and host factors drive the development of true biBC along similar genetic routes? Allelotyping provided unambiguous proof for distinct clonality in 23 of 28 cases. In another 4 biBCs, the genotyping data did not exclude the hypothesis of metastatic spread, whereas clinical and histologic data were in favor of bilaterality.