Breast adenocarcinoma recurring as small cell carcinoma in a patient with a germline BRCA2 mutation: clonal evolution unchecked

Experimental Hematology & Oncology

Mothaffar Rimawi¹  Luis M Franco³  Marilyn Li³  Alejandro Contreras²  Tanya Eble³  Polly Niravath¹ 

[1] Lester & Sue Smith Breast Center, Baylor College of Medicine, One Baylor Plaza, BCM 660, Houston, Texas 77030, USA;Department of Pathology, Baylor College of Medicine, One Baylor Plaza, BCM 660, Houston, TX 77030, USA;Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, BCM 320, Houston, TX 77030, USA

关键词: Therapeutic stress;    PIK3CA mutation;    Small cell carcinoma of the breast;    BRCA2 mutation;   

Others  :  1135265
DOI  :  10.1186/2162-3619-4-1

 received in 2014-09-25, accepted in 2014-12-29,  发布年份 2015

【 摘 要 】

Background

Because up to 30% of breast cancer cases may relapse, understanding the biology of recurrent breast cancer is imperative in preventing these poor outcomes. Thus, we present this unusual case of a BRCA2 carrier who presented seven years after her initial diagnosis of breast adenocarcinoma with a new lump in the left axillary tail, which proved to be small cell carcinoma. The second cancer bore no morphologic or immunohistochemical resemblance to the first. However, we aimed to understand whether the two cancers could have been related.

Methods

We performed targeted Next Generation Sequencing on both cancer specimens in order to determine whether there was a genomic relationship between the two cancers.

Results

We found that the initial breast adenocarcinoma was positive for a heterozygous mutation in PIK3CA (c. 1624 G > A, p.E42K) and a heterozygous 13-basepair deletion in TP53 (c.639-651del, p.H214fs). The small cell cancer was positive for the same mutation in PIK3CA, but negative for the mutation in TP53.

Conclusion

We concluded that the small cell cancer may have arisen from a clone within the initial cancer, since they carried an identical genetic mutation. Furthermore, we postulate that the unusual morphology of the second cancer may be due, in part, to the patient’s germline BRCA mutation.

【 授权许可】

   
2015 Niravath et al.; licensee BioMed Central.

【 图 表 】

Figure 1.

Figure 2.

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