Methods for treating barrett's metaplasia and esophageal adenocarcinoma
Disclosed herein are methods for treating Barrett's metaplasia and esophageal adenocarcinoma and methods for determining mutational load as a predictor of the risk of disease progression from Barrett's metaplasia to esophageal adenocarcinoma.
1. A method for treating subject with a high risk of disease progression from Barrett's metaplasia to esophageal adenocarcinoma, the method comprising:
determining mutational load as a predictor of the risk of disease progression from Barrett's metaplasia to esophageal adenocarcinoma in a subject, by:
amplifying DNA sequences in microsatellite regions 1p (CMM1, Lmyc), 3p (VHL, OGG1), 5q (MCC, APC), 9p (CDKN2A, CDKN2B), 10q (PTEN, MXI1), 17p (TP53), 17q (NME1), 18q (DCC), and 21q, 22q (NF2) from a biological specimen from the subject;
detecting mutations in the microsatellite regions of the amplified DNA sequences;
categorizing clonality of each mutation, wherein categorizing clonality of each mutation comprises assigning one of three categories selected from the group consisting of no clonality, low clonality and high clonality, wherein high clonality is assigned where loss of heterozygosity is present in greater than about 75% of DNA analyzed, low clonality is assigned where loss of heterozygosity is present in about 50% to about 75% of DNA analyzed; and no clonality is assigned where loss of heterozygosity is present in less than about 50% of DNA analyzed;
calculating a mutational load based on the sum of low and high clonality mutations; wherein DNA microsatellite instability at a single locus is defined as 0.75z1, and wherein DNA microsatellite instability at multiple loci is defined as 0.75z1+0.5z2, wherein z1 represent a single locus displaying DNA microsatellite instability and z2 is the number of loci displaying DNA microsatellite instability greater than 1 locus; wherein the score for low clonality is 0.5x, wherein x is the number of low clonality mutations and the score for high clonality is y, wherein y is the number of high clonality mutations; and wherein the overall mutational load is y+0.5x+0.75z1+0.5z2;
assigning the subject to a risk category to a high mutational load risk category when the subject has a mutational load greater than or equal to 1.75; and
administering to the subject that is assigned to the high mutational load risk category at least one treatment modality selected from endoscopic mucosal resection, endoscopic submucosal dissection, a therapeutically effective amount of radiofrequency ablation, a therapeutically effective amount of cryoablation, or a therapeutically effective amount of photodynamic therapy.
2. The method of claim 1 , wherein the subject is a human diagnosed with Barrett's esophagus.
3. The method of claim 1 , wherein the biological specimen is a mucosal lining of the esophagus.
4. The method of claim 1 , wherein amplifying DNA sequences comprises:
selecting a primer pair corresponding to a specific microsatellite region;
adding the primer pair to the DNA sequences;
and performing quantitative polymerase chain reaction on the DNA sequences with the primer.
5. The method of claim 1 , wherein detecting mutations comprises determining the sequence of the amplified DNA and comparing the amplified DNA to a known wild type control sequence for the specific microsatellite region and identifying differences between the sequence of the amplified DNA and the known wild type control sequence.
6. The method of claim 1 , wherein DNA microsatellite instability is determined by the presence of at least one of the shortening and lengthening of a DNA microsatellite region.
7. The method of claim 1 , wherein the method is independent of a histological standard.
8. The method of claim 1 , wherein the biological specimen is a biopsy sample, fine needle aspirate sample, a cytology sample, a frozen tissue simple, or a fixed tissue sample.
9. The method of claim 1 , further comprising removing the biological specimen from the subject prior to the amplifying step.