Tissue Microarray FAQs

Q1: How long do you keep tissue out before you put them in fixative?
Samples are typically put into formalin within 30 minutes after surgical resection at room temperature.
Q2: How long do you fix your samples? What fixative do you use?
Surgically removed samples were preserved in neutral phosphate buffered formalin for 24 hours before they are processed in a tissue processor (Leica) and embedded in paraffin.
Q3: Do you offer frozen tissue microarrays? How many samples can you put on one array?
Unfortunately, we stopped providing frozen tissue microarrays.
Q4: Do you offer fixed tissue microarrays? How many samples can you put on one array?
Yes, we make formalin-fixed tissues embedded and arrayed in paraffin for high throughput immunohistochemistry staining and in situ hybridization. We can put ~48 cores with a 2.0 mm diameter, ~96 cores with a 1.5 mm diameter, ~216 cores with a 1.0 mm diameter, or ~616 cores with a 0.6 mm diameter on one tissue array slide.
Q5: What kind of decalcification method do you use?
There is standard 24-48 hour 10% nitric acid treatment (decalcification) after 24 hour of fixation in neutral buffered formalin.
Q6: How are slides processed?
All tissues are fixed in 10% neutral formalin for 24-48 hours, dehydrated with gradient ethanol, cleared with xylene, and embedded in paraffin. Afterwards, each slide is tested for immunohistochemistry on one antibody specific to the tissue used in the array. Quality control is ensured as every tissue block is collected and arranged by our pathologists.
Q7: What is the post-mortem interval/time to fixation for autopsy samples?
For post mortem tissues, the typical time in formalin fixative depends on the duration of procedures performed after death, including the acquisition of consent from the family. Nevertheless, the post mortem interval is less than six hours.
Q8: How long is there between tissue collection and fixation for surgical cases?
The process occurs less than 30 minutes after surgery and before the fixation.
Q9: Is the tissues used in making tissue arrays validated for immunohistochemistry studies?
Yes, two tissue sections of every lot of tissue arrays was sampled for IHC studies to ensure the validation of antigenicity remains in the tissue and combined with H&E slides of every 10-20th sections to assure the tissue were properly fixed and processed.
Q10: What ethical considerations and protocols are used in tissue collection?
All tissue is collected under the highest ethical standards with the donor being informed completely and with their consent. We make sure we follow standard medical care and protect the donors' privacy.
All human tissues are collected under HIPPA approved protocols. All animal tissues are collected under IACUC protocol. All samples have been tested negative for HIV and Hepatitis B or their counterparts in animals, and approved for commercial product development.
Q11: Do we need to have a Material Transfer Agreement (MTA) in place to order from US Biomax?
It is not required to have an MTA signed for research orientated institutions, as well as pharmaceutical companies who need to produce therapeutic and diagnostic reagents using our tissue samples or tissue arrays. It is the individual researcher's responsibility to get approval from their respective Intuitional Review Board (IRB) to use human tissue samples for their research work. We can provide necessary documents to satisfy your needs in order to get approval from your IRB.
Q12: How long can a tissue array slide can be stored?
After sectioning, tissue slides from US Biomax were baked at 60°C for 2 hours. We have tested that the antigenicity was not lost (no significant difference in statistics) with a tissue array slide kept in a refrigerator (4°C) dated 2 years ago, although wrapped in a thick layer of paraffin or put in a plastic bag with filled nitrogen gas and stored at -20°C may have better preservation of antigenicity as reported elsewhere.
Q13: Are tissue microarrays valid for clinico-pathological studies? In other words, do tissue arrays account for heterogeneity of tissues or does ONE small core in a tissue array represent a whole tissue section?
Several studies have examined the question of the representation of tissues in TMAs using various markers in different tumor types. In general, although they vary somewhat in terms of recommendations for sampling, all studies indicate there is usually excellent agreement between the use of TMAs and standard tissue sections for clinico-pathological studies.1 Their conclusion is that for homogeneous markers, a single TMA spot (0.6 mm) per case will be adequate.
Q14: How can you make sure the tissue array cores are pathologically represented the original tissue block?
Tissue arrays from US Biomax usually consist of cores from 1.0 to 1.5 mm in diameter, which is an area 2.7 to 6.3 times larger than that of a 0.6 mm core tissue microarray. Thus, 1.0 mm and above core size is sufficient to represent the whole tissue section. Our high-density tissue arrays use high numbers of single cores to maximize the numbers of tissue to benefit the end users.
Every 10-20th section of the tissue array is stained with H&E and reviewed by two well experienced pathologists to make sure the pathology diagnosis is current and matched to the adjacent serial sections.
Q15: What's the threshold of your tissue array standard?
US Biomax is the first company to adopt the highest quality control standard in making tissue arrays, which is 90% valid cores remaining in a given tissue array, with rare exceptions for certain types of TMAs, such as pharyngeal or laryngeal cancers. A valid core means that the tissue core not only remains 50% or higher intact, but its pathology is also confirmed by an experienced pathologist. In other words, less than 10% of cores fall off or become invalid (e.g. cancer becomes normal). In reality, all of our tissue arrays meet a 95% valid core QC standard.
Q16: We are still not convinced; can we try your tissue microarray before purchasing?
We have limited numbers of trial slides (QC standard not met, but at least 70% of cores remain; good for titrating antibody and retrieving conditions) for certain arrays at $25- $135 each (1/4 of regular price), depending on the amount of cores. To add a trial tissue array slide is easy. Just click the adjacent price link to the right of our regular tissue array slide in our online shopping cart. You may only purchase up to two trial slides per item at a time. The catalog number is trial slide is regular catalog number with t at the end.
Q17: Do you have protocols you recommend to use for IHC or ISH on your tissue arrays?
Yes, we do. You can download the protocols in PDF format under our support page.
Q18: What's the minimum amount of tissue arrays for one order?
One unstained paraffin tissue array slide.
Q19: What's the maximum amount of tissue arrays we can buy?
As many as you want. Please contact us for a quote.
Q20: How do custom tissue microarrays work?
Currently we stopped providing custom TMA service.
Q21: Do you use adhesive tape for transferring tissue sections on your tissue microarray?
No more messy transferring steps and expensive tapes for us in making tissue arrays. The amount of adhesive material remaining in slides can possibly interfere with the subsequent immunohistochemistry staining or in situ hybridization procedures. Our tissue arrays are sectioned and mounted manually.
Q22: What's the advantage of your microarray over other vendors?
Every vendor of tissue arrays has its own niche, either by providing varieties of tissue types or numbers of core format to meet needs for end users. The advantage of tissue arrays in US Biomax include:
  • High quality, stringent QC standard (90% to 95% valid cores remain in a given tissue array).
  • Strong adherence of tissue array sections with glass slides to sustain the rigorous antigen retrieving procedures (heat, microwave oven or boiling, or high and low pH). Tissue array sections are mounted on Fisher SuperFrost Positive Charged glass, the highest quality available in the industry.
  • Fresh, paraffin coated thin layer on tissue microarray sections to prevent oxidation or moisture condensation which may lead to enzyme digestion or mold growing.
  • Low price specificity (price/slide) while providing high number of cases and larger core areas. 
  • Varieties of disease types available. We provide more than 1450+ types of tissue arrays, and 20 or so types of diseased or normal tissue arrays to choose from. Some rare types of cancer are also in our inventory, such as adrenal carcinoma, penile, vulvar, brain glioma, lymphoma, pancreatic cancer, sarcoma, chondrosarcoma, melanoma, head and neck tumor tissue arrays, besides common types of cancer arrays (such as cervical, colon, prostate, breast, lung, liver, kidney, thyroid, esophagus, pharyngeal, laryngeal and skin).
  • Maximum normal controls available for most types of cancer. For instance, BR806 contains 40 cases of breast cancer and 40 cores of matched adjacent normal tissue from the same donor, while maintaining a 1.5 mm core diameter. Another example is BR1005, containing 50 cases of breast cancer and their matched metastasis in lymph nodes.
  • We ship our tissue arrays with FedEx standard overnight delivery to all 50 states in the U.S. and International Priority to most other countries. Orders received before 4:00pm EST will be sent out in within 1-2 days because we need prepare the fresh cut tissue arrays or sections. We only list items in stock, although you may backorder from us.
  • All tissue arrays are listed with price and package information. You can choose to buy trial (regular catalog number ending with t if they are available on our website) and H&E stained slide (regular catalog number ending with s) as well as with regular tissue arrays. Best of all, you can place orders online with a Purchase Order or a Credit Card securely. It's safe, convenient and fast.