Abnormal FHIT gene transcript and c-myc and c-erbB2 amplification in breast cancer.

Searching for ways to improve the characterization of breast cancer we examined the relationship between the status of the FHIT gene transcript and amplification of c-myc and the c-erbB2 oncogene. Abnormal FHIT transcript was detected in 32 of 79 cancers examined. The presence of Fhit protein estimated by Western blots was evident only in cancers exhibiting a normal-sized FHIT transcript. This indicates that abnormal FHIT transcripts observed in our study did not encode any Fhit protein or the amount of such protein was very low. There was no association between the presence of aberrant FHIT gene transcript with age, tumor size, estrogen and progesterone receptor status, local metastases and histological grading. However, the abnormalities in FHIT gene transcripts were observed with different frequency depending on the histopathological type of the tumor. The aberrant FHIT transcript was detected in 60% of lobular cancers and only in 28% of ductal cancers. Analyzing the occurrence of c-myc and c-erbB2 amplification and the presence of aberrant FHIT gene transcripts we found that the aberrant FHIT transcript more frequently occurred in tissues with c-myc amplification. There was a significant (P < 0.05) correlation between the occurrence of the aberrant FHIT gene transcript with accompanying c-myc amplification and positive lymph node status. However, in order to evaluate the predictive value of these findings in breast cancer, an extended clinical follow up will be necessary.