Will liquid biopsies replace tissue biopsies?

Retrieval of tissue for biopsies can be difficult. For some patients the tumor is embedded deeply in the liver making it nearly impossible to retrieve valuable tissue.
“Liquid biopsies are potentially a new way to perform genetic interrogation on patients with advanced-stage lung cancer. I think we know that the gold standard currently for diagnosing and for molecular interrogation for lung cancer patients is with tissue biopsies obtained surgically or by fine-needle aspiration or core biopsies”.
But there are other obstacles as well, including the fact that there is a percentage of patients who will not have enough tissue for molecular testing.
One of the most puzzling question is that of tumor heterogeneity ie. how many mutations are present in every biopsy?
This article refers to Lung Cancer but much of of the information crosses over to our cancer as well:
http://www.cancernetwork.com/articles/liquid-biopsies-lung-cancer?GUID=F0B4FECE-59A0-4A23-99C1-DA933C290DEA&rememberme=1&ts=19122016

Understanding Complex Tumor Heterogeneity was the focus of another study.
When asked the simple question, how many mutations are present in every biopsy compared with those present in one biopsy or one or more biopsies but not all biopsies, we found that on the average, somewhere between 63% to 65% of mutations were not present in every biopsy sampled.
Read more: http://www.cancernetwork.com/podcasts/understanding-complex-tumor-heterogeneity