CHD5 gene variant predicts leptomeningeal metastasis after surgical resection of brain metastases of breast cancer.

Purpose: Leptomeningeal metastasis (LM) is a complication of surgery for brain metastasis and is a risk factor of poor prognosis. The risk of LM is particularly high after surgery for a breast cancer metastasis to the brain. If the risk of LM after surgical resection for a brain metastasis were predictable, appropriate adjuvant therapy could be administered to individual patients to improve their prognosis. The present study aimed to reveal the genetic characteristics of brain metastases as means of predicting LM in breast cancer patients.

Methods: Ten patients with brain metastases of breast cancer presented LM after surgical resection were analyzed by whole-exome sequencing.

Results: A chromodomain-helicase-DNA-binding protein 5 (CHD5) gene alteration was detected in nine cases (90%), including a nonsynonymous variant in four cases and copy number deletion in five cases. CHD5 protein expression was lost in nine cases and had decreased in one case. The frequency of CHD5 gene alteration in brain metastases with LM was significantly higher than in primary breast cancer (2.3%) or in brain metastases of breast cancer (0%) (p < 0.0001).

Conclusions: These results suggested that the CHD5 gene alteration was associated with LM after surgical resection of breast cancer brain metastases. Searching for the gene alteration might predict the LM risk after surgical resection.